Tag Archives: Glen Zediker

RELOADERS CORNER: Standard Deviation

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Before getting into improving bullet velocity Standard Deviation, it’s first necessary to understand what it is, and what it isn’t. KEEP READING

chronograph screen

Glen Zediker

I got started on this topic last time, and kind of came in through the side door. Quick backstory: the topic was how to start on solving unsuitably high shot-to-shot velocity inconsistencies. This time we’ll start at the other end of this, and that is taking steps to improve already suitable velocity deviation figures.

Clearly, the first step in getting involved in velocity studies is getting the velocities to study. Of course, that means you need a chronograph. Midsouth Shooters has a selection and there’s a direct link in this article.

Virtually all chronographs are going to be accurate. A well-known manufacturer of shooting-industry electronics once told me that unless a chronograph displays a reading that’s just crazy unrealistic, you can rely on the number. The reason is that the current state of circuitry is pretty well understood and heavily shared. Pay attention, though, to setting up the device according to suggestions in the instructions that will accompany the new chronograph. The more recent Doppler-radar-based units are not technically chronographs, but they function as such. The advantages to those are many! More in another article soon. For now, for here, what matters is getting some numbers.

labradar
Latest and greatest, in my mind, advancement in data collection is doppler radar based units, like this from LabRadar. Easy to use, and not finicky about sunlight and setup.

Point of all that was this: You don’t have to spend up for the best to get a good chronograph. One of the price-point differences in chronographs is how much it will help work with the data it gathers. Most of us any more don’t have to do hands-on calculations. Me? All I want is a number. However, there are a good many that will record, calculate, and print.

magnetospeed
Barrel-mounted electro-magnetic chronographs like this one from MagnetoSpeed make it easy. I like being able to read speeds without all the setup, and not having to rely on a benchrest-type restriction. It stays on the rifle so can easily be used in the field. There are rail mounts available also.

Terms and Twists
Speaking of calculations, the most known and probably most used expressed calculation of collected velocity figures is Standard Deviation. SD suggests or reflects the anticipated consistency of bullet velocities (calculated from some number of recorded velocities). “Standard” reflects on a sort of an average of the rounds tested. I know saying “sort of” disturbs folks like my math-major son so here’s more: SD is the square root of the mean of the squares of the deviations.

Standard Deviation calculations did not originate from ballistic research. It’s from statistical analysis and can be applied to a huge number of topics, like population behavior. SD calculation forms a bell curve, familiar to anyone who ever had to take a dreaded Statistics class. The steeper and narrower the apex of the bell, the narrower the fluctuations were. But there’s always a bell to a bell curve and the greatest deviations from desired standard are reflected in this portion of the plot. Depending on the number of shots that went into the SD calculation, these deviations may be more or less notable than the SD figure suggests.

Calculating SD
If you have no electronic gadgetry to help: add up all the recorded velocities and divide them by the number of records to get a “mean.” Then subtract that mean value from each single velocity recorded to get a “deviation” from the mean. Then square each of those. Squaring them eliminates any negative numbers that might result from cancelling out and returning a “0.” Add the squares together and find the mean of the squares by dividing again by the number of numbers — minus 1 (divide by n -1; that eliminates a bias toward a misleadingly small result). Then find the square root of that and that’s the Standard Deviation figure, which is “a” Standard Deviation, by the way, not the Standard Deviation.

bell curve
This is a bell curve such as results from plotting an SD calculation, and is given here only an example of how the distribution, the “odds,” graph out.

Knowing a load’s SD allows us to estimate-anticipate how likely it is for “outliers” to show up as we’re shooting one round after another. Based on the distribution based on the curve, if we have an SD of 12, for instance, then a little better than 2 out of 3 shots will be at or closer to the mean than 12 feet per second (fps). The other shots will deviate farther: about 9 out of 10 will be 19 fps, or less, from the mean. 21 out of 22 will be 24 fps closer to the mean. Those numbers represent about 1.00, 1.65, and 2.00 standard deviations.

Now. All that may have ranged from really boring to somewhat helpful, to, at the least, I hope informative.

Mastery of SD calculation and understanding doesn’t necessarily mean smaller groups. It gives a way to, mostly and above all else, tell us, one, the potential of the ammo to deliver consistent elevation impacts, and, two, reflects on both how well we’re doing our job in assembling the ammo and the suitability of our component combination.

I honestly pay zero attention to SD. I go on two other terms, two other numbers. One is “range,” which is the lowest and highest speeds recorded in a session. The one that really matters to me, though, is “extreme spread.” That, misleading on the front end, is defined as the difference between this shot and the next shot, and then that shot and the next shot, and so on. Why? Because that’s how I shoot tournament rounds! This one, then another, and then another. A low extreme spread means that the accuracy of my judgment of my wind call has some support.

Depending on the number of shots and more, SD can be misleading because it gets a little smaller with greater amounts of input. Extreme spread doesn’t. I have yet to calculate an SD that put its single figure greater than my extreme spread records.

Lemmeesplain: The shot-to-shot routine is to fire a round. It’s either centered or not. If it’s not centered, calculate the amount of correction to get the next one to center. Put that on the sight. Fire again. If I know that there’s no more than 10 fps between those rounds, that’s no enough to account for (technically it can’t be accounted for with a 1/4-MOA sight) then it’s all on me, and if it’s all on me I know that the input I got from the last shot, applied to the next shot, will be telling. Was I right or wrong? It can’t be the ammo, folks. Then I know better whether the correction is true and correct.

Some might be thinking “what’s the difference?” and it’s small, and so are scoring lines.

A load that calculates to a low SD is not automatically going to group small, just because it has a low SD. Champion Benchrest competitors have told me that their best groups don’t always come with a low-SD load. But that does not apply to shooting greater distance! A bullet’s time of flight and speed loss are both so relatively small at 100 yards that any reasonable variation in bullet velocities (even a 20 SD) isn’t going to open a group, not even the miniscule clusters it takes to be competitive in that sport. On downrange, though, it really starts to matter.

For an example from my notes: Sierra 190gr .308 MatchKing, in a .308 Win. Its 2600 fps muzzle velocity becomes 2450 at 100 yards and 1750 at 600 yards (I rounded these numbers).

If we’re working with a horrid 100 fps muzzle velocity change, that means one bullet could lauch at 2550 and the next might hit 2650, in the extreme. The first drifts about 28 inches (let’s make it a constant full-value 10-mph wind again to keep it simple) and the faster one slides 26 inches. That’s not a huge deal. However! Drop — that is THE factor, and here’s where inconsistent velocities really hurt. With that 190, drop amount differences over a 100 fps range are about 3 times as great as drift amounts. This bullet at 2600 muzzle velocity hits 5-6 inches higher or lower for each 50 fps muzzle velocity difference. That is going to cost on target. And it gets way (way) worse at 1000 yards. Velocity-caused errors compound on top of “normal” group dispersion (which would be group size given perfect velocity consistency).

This 100 fps example is completely extreme, but half of that, or even a quarter of that, still blows up a score, or creates a miss on an important target.

That all led to this: What is a tolerable SD?

I say 12. There has been much (a huge amount) of calculation that led to that answer. But that’s what I say is the SD that “doesn’t matter” to accuracy. It’s more than I’ll accept for a tournament load, but for those I’m looking for an extreme spread less than 10 fps (the range might be higher, but now we’re just talking terms). More later…

Check out chronographs HERE

This article is adapted from Glen’s book, Handloading For Competition, available at Midsouth HERE. For more information on that and other books by Glen, visit ZedikerPublishing.com

RELOADERS CORNER: Bullet Seating Depth

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A popular topic in these pages, and for good reason: it can make a big difference in rifle accuracy! Read more about it HERE

benchrest bullets
Pretty much all bullets respond to seating depth changes. Long or short, for maximum accuracy it’s worth the effort.

Glen Zediker

Every time I do an article here in Reloaders Corner on the topic of bullet seating, I always see at least a couple of comments from readers about their experience and preferences with bullet seating depth. Those usually involve or revolve around seating a bullet so it is touching, or is nearly touching, the lands or rifling when the round is chambered.

This is a long-standing “trick” well known in precision shooting circles, like those competing in NRA Long Range or Benchrest.

Seeing What You’ve Got
First step, absolutely, is determining what the bullet seating figure is for your particular bullet in your particular chamber. This length is most often referred to as “dead length.” That’s a pretty ominous-sounding term! It’s not really perilous, but there is a little danger involved, which, mostly, is one point to respect. That point is that when a bullet goes from just off to just on — actually touching the lands — pressure will (not may) increase. Reason is that the previous gap-valve effect closed so burning gases are effectively “plugged up” a fractional millisecond longer. My experience with the most common small- to medium-capacity cases we’re using (ranging from, say, .223 Rem. to .308 Win.) is that this is worth about a half-grain (0.50-gr.) of propellant.

Finding It
Those who have read much in these pages have seen the Hornady LNL OAL tool. This is a well-designed appliance that will show you, in your chamber with your bullet, how far forward the lands are, or, more precisely, the overall cartridge length that will touch the lands. This amount varies and is unique! Don’t transfer figures from one gun to the next. It also changes… As the chamber throat erodes it lengthens, and so too will the overall cartridge length that touches the lands. Let’s call overall cartridge overall length COAL for sake of space.

hornady lnl gage
Here’s the tool to find the seating depth that touches the lands. Hornady LNL Oal Gage.

There are other means but I’ve not found one more accurate. Some smoke over a bullet that’s been seated into a “loosened” case neck and gauge contact by the marks left. This, however, is likely to be “touching, plus” length.

Once you’ve got the round ready to measure, I strongly suggest doing so using a bullet length comparator along with your caliper. This is another tool that’s been gone over and gone on about here. It measures at a point along the bullet ogive rather than on the bullet tip. It’s more accurate. Now. A comparator inside diameter is usually close to actual land diameter, but, as with chambers, these are each and both unique so don’t assume anything.

Hornady comparator
More precise reads come from using a bullet length comparator to measure overall length. This is a Hornady LNL too.

Why It Works
Setting the bullet so it touches the lands does a few things, all good. One, and I think one of the most influential, is that the bullet starts off aligned with the rifle bore. As a matter of fact, it better centers the whole cartridge because there is, not may be, at least a little gap between chamber and case. If there wasn’t the round wouldn’t enter the chamber. The bullet is, effectively, supported by the lands and that has, also effectively, taken up the “slack” by locating the cartridge more concentric with the chamber and bore. It also then effectively makes up for the affronts to concentricity created by case neck wall inconsistencies and the resultant relocation of the case neck center.

Another is that that it eliminates jump (the usual distance or gap between the first point of land diameter on the bullet nosecone and the lands). Bullet wizard Bill Davis (designer of the original “VLD” projectiles, and others of much significance) once told me that his thoughts on why especially the high-caliber-ogive high-ballistic-coefficient bullet designs worked best with no jump were for all those reasons and improvements just mentioned. Plus another: gravity. A bullet floating in space, and also moving forward in this space, has that much more opportunity to engage the lands at a little angle, if only because of gravity. Always have thought about that one.

Soft-Seating
There are degrees. When we go from just on to “in” that’s another tactic some experiment with. And it has another level that’s commonly popular with Benchrest and other precision shooters. That’s called “soft seating.” What that is, is setting the case neck inside diameter to very nearly match the bullet diameter with the idea that the bullet starts out extra-long and then chambering the round finishes the bullet seating when the bullet contacts the lands. The reason for the more generous case neck inside diameter is to reduce resistance so the bullet can more easily set back and let the lands seat it.

I don’t use this tactic, but have. It’s another level of commitment and, as is often true with such other levels, demands more attention and also limits utility. One is that it clearly is only for bolt-action use. Another is that it’s for single-shot use only; such rounds should not be loaded into a magazine or fed from a magazine. For another, once loaded the round can’t usually come back out. The bullet will stay and you’ll get an action full of propellant.

Seating Depth Experiments
Now this is a process I have used throughout. Most times I find that best accuracy comes with a seating depth that has the bullet “just” on the lands. Contact is made but it’s the same pressure level as if the bullet were sitting on the benchtop. I also often have found best group sizes come at a little less than touching, and, a few times, at a little more than touching. I’m talking about 0.002-0.003 longer than dead-length. Let’s call it “firmly touching” but also a long ways away from “jammed.” These rounds often can’t be extracted.

There’s an easy way to run seating depth experiments. Here’s how I do it: I load however-many rounds at dead-length plus 0.003 COAL. I load them all that way. I then take a small press I can clamp on to a benchtop or tailgate at the range, and install a micrometer-top seating die. For max accuracy, I already seated all these test rounds using this exact setup. Take along a caliper and comparator and a fresh notebook page. I’ve adjusted the propellant charge as said earlier by dropping it a tad. Now. I also know that there’s going to be a little difference in perfected results because of this because lengths that aren’t touching the lands are running 35-40 feet per second slower, but it still shows me what’s going to work best. If it ends up being a COAL with a little gap, I’ll bump it back up.

Last
As said, the COAL that works best is going to change because the throat is going to change. Check using the OAL gage and adjust. That means the load is also changing, a little bit, each time the bullet moves forward (more case volume), and that can affect zero and velocity.

It’s a lot to keep up with.

Another note: If you’re feeding these rounds from a magazine, and running them through a semi-auto match-rifle, make sure there is adequate bullet retention (difference between bullet diameter and case neck inside diameter, go good 0.003 inches). Don’t want the bullets jumping forward (inertia-induced). If, for example, you’re giving 0.002 hold-off, that little bit can get taken up easily and then, if the bullet gets on the lands, there’s a pressure spike.

GAGES, on sale now at Midsouth!

The preceding is a specially-adapted excerpt from Glen’s book Handloading For Competition. Available HERE at Midsouth Shooters Supply. Visit ZedikerPublishing.com for more information on the book itself, and also free article downloads.

 

RELOADERS CORNER: Understanding Ballistic Coefficient

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Math and myth both get involved in bullet Ballistic Coefficient discussions. Keep reading to separate the two and learn exactly what BC is, and what it isn’t. MORE

bc

Glen Zediker

Years ago I explained in great detail to a fellow here all about ballistic coefficient and how it was calculated and how it could be used and how it can change and so on, and he stopped me: “So you mean it’ll hit furtherer on up the hill…” That’s it.

A “ballistic coefficient,” or “BC,” is a number assigned to a bullet that suggests its aerodynamic performance.

That’s a key word, “suggests.” The main suggestion is how well this bullet will fly compared to that bullet, and the one with the higher BC ought to fly better. Fly better means less drop and drift, and those, factually, are a product of the higher-number BC. My best all-inclusive definition what a higher BC does for us: less speed lost over distance. Regardless of the muzzle velocity or the distance, one bullet with a higher BC will lose relatively less velocity over the same distance.

bullet blueprint
Here’s a blueprint. All the information needed to calculate a BC is contained here. It doesn’t have to be a real bullet because a BC model is not a real bullet either. Design factors that influence BC are virtually every design factor: length, ogive, boat-tail, meplat, weight. These factors, in this instance, calculate to a G1 BC of 0.560. By the way, there’s about a 5 point BC increase for each added 1 grain of bullet weight.

BC is calculated based on a standard bullet model. There are 7 of those. Two are normally used to determine BC for conventional rifle bullets, like what the most of us reading this use. Ballisticians and designers know which model to apply to different bullet types. The common model is a “G1” (another is G7, which is becoming the popular standard for boat-tail bullets; G1 is based on a flat-base). The flight of this G1 bullet has been calculated at varying velocities and distances. It’s “all math” because a G1 does not in fact exist. BCs are derived by comparison.

g1
The older standard for most rifle bullets was the G1. The newer, and better, standard is the G7. However! BC is never chiseled into stone regardless of the model. It’s a way to compare bullets, and a place to start figuring yours out.

g1 and g7

The standard bullet of any form-factor has a BC of 1.000. An actual bullet that’s compared to the model at points downrange will either be flying faster or slower than the model. If it’s moving faster, its BC will be greater than 1.000. If it’s going slower, it will be less than 1.000. It’s a percentage of the standard or model bullet’s performance.

Now. That is also all that it is!

BC is not an infallible factual statement about precisely what a bullet will be doing when it’s loaded and fired at that target than moment with that rifle. Not nearly, not hardly.

To me, BC gives us a place to start estimating drop (elevation) and also clues to how much it will get moved by a wind. It’s a way to compare bullets.

BC changes! Day to day, place to place, hour to hour.

Some bullet makers publish a BC for a bullet based on actual testing (chronographs) but now it’s pretty much “just math.” That’s fine. Which — math or measure — provides the best information? Some believe that a measured, tested BC is more realistic and, therefore, more valuable. But, if the point is to compare bullets, calculated BCs is more reliably accurate.

We (NRA High Power Rifle shooters) have gone to difficult and frustrating lengths to collect data to calculate “real” BCs (chronographing at 500+ yards hain’t always easy). Measured BCs are quite often lower, and they are quite often higher. Reasons follow.

The accuracy of drift and drop tables clearly revolves around what the actual, at that moment, BC performance is from the bullet you’re shooting (compared to what it’s “supposed” to be).

Anything that can influence bullet flight influences the actual, demonstrated BC performance.

BC uniformity is important. Bullets that show uniform BC performance produce less elevation dispersion. A source for variation is the meplat (bullet tip). Hollowpoint match bullets are notorious for inconsistency in this area. There’s a tool, a “meplat uniformer,” that fixes it. That’s pretty much the point to the plastic points on bullets like Hornady’s A-Max line.

Atmospherics, which add up as a list of factors, have a huge influence on BC performance. Air density is probably the most powerful influence. Any conditions that allow for easier passage of a bullet through the air don’t detract as much from its stated BC as do any conditions that serve to disrupt its headway. BCs are based on sea-level so can easily show as a higher number at a higher elevation. I can tell you that bullets fired at The Whittington Center in New Mexico have a noticeably better BC than those shot at Port Clinton, Ohio.

Range reality is that the demonstrated BC changes from morning to afternoon and day to day and place to place. The calculated BC is not changing, of course, but the mistake is assuming that a BC is a finite measure of bullet performance.

Bullet stability is even a factor. For a stated BC to be shown on a shot, the bullet has to be “asleep.” If it’s not stable, it’s encountering disruptions that will slow it down. The rotational speed of a bullet in a test can influence BC. We’ve seen differences comparing different twist-rate barrels, and the faster twists often show a little lower tested BC.

Factors that don’t matter in BC? Caliber. I’ve been argued at often over this next, but it is perfectly and absolutely true: BCs work the same regardless of caliber or bullet weight. Two bullets that each have a 0.550 BC, for instance, behave the same. That’s helpful, and at one time was more helpful than it is now. When we had to use paper tables to get drift and drop data and there was a new bullet that didn’t yet have those tables done, all you had to do was find data for another bullet with the same BC, go to the same muzzle velocity, and that data was 100-percent accurate. A .308 and .224 that both have the same BC share the same table. Remember, it’s not “real,” it’s a mathematical model.

So if you take a load to the target one day and you’re putting on more elevation than the BC-based calculation says you should, the BC isn’t wrong. The day is just different.

Finally, does it matter (really) if a bullet BC is based on a G1 or G7 model? Debates continue. But, not really, and I say that because BC is still only a suggestion. G7 is a more closely matched model to what we’re usually shooting when we think of a “high-BC” bullet, but all the same factors day to day also influence its accuracy. Given access to the data, I definitely, though, go with G7 calculations to have a place to start from. My experience has been that there is less difference in varying conditions, but, again, it’s still (plenty) enough change that you cannot dial it in and win anything…

The preceding is a specially-adapted excerpt from Glen’s book Handloading For Competition. Available HERE at Midsouth Shooters Supply. Visit ZedikerPublishing.com for more information on the book itself, and also free article downloads.

RELOADERS CORNER: 4 Bullet Seating Tips

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It’s the “last thing” that happens in handloading, and here’s a few ways to make it better. READ MORE

bullet seating

Glen Zediker

Last time the topic was bullet seating, but with a focus on safety — respecting the overall cartridge length that touches the lands or rifling in a barrel — and specifically making sure your bullet isn’t touching the lands (unless that’s what you want). This time here are a few ideas on how to improve the quality and consistency of bullet seating, and mostly from a tooling perspective.

A few things matter. The ultimate goodness is a round capped by a bullet that’s straight and undamaged, ready to get launched straight into the bore and then straight on to target center.

1. Die Design
I have long and often said that the single-most important tooling upgrade to improve the accuracy of handloaded ammunition is a better seating die. “Better” is better designed, and better designed, in my mind, is one that follows the “in-line” architecture.

LE wilson bullet seater
Here’s an LE Wilson die. There’s none more precise, but there are many faster to use! The sleeve-style seaters provide a close duplication in performance and results.

One of the first that comes to mind is the LE Wilson seater (there are others similar, but it’s the most well known). This seater style is the staple of Benchrest competitors. It’s not practicable for the most of us because it’s slow and a little tedious. How it works is that there is a seating stem that’s a very close fit to the die body. The die body and stem are concentric thanks to precision machining. The die body goes over the case, which has had a bullet placed in its neck, and the die holds the case in stable alignment. The stem is pushed down, seating the bullet. There’s zero “wiggle room.”

The difference in effect between that and a “standard” seating die, which has a stem threaded into a 7/8-14 press-mounted die body, is that the case isn’t free to move. In a conventional thread-in design, there’s a lot of room for movement in the case as it’s being run up into this type die. There’s slack in the case-shellholder fit, and slack in the fit of the case inside the die body. When the bullet that’s perched in the case mouth contacts the seating stem there’s a good chance it can get tilted askew. That then means there’s a good chance the bullet won’t be seated dead straight.

redding seating die
Here’s a Redding Competition Seating Die. The case is supported fully within a spring-loaded sleeve prior to accepting the bullet. Better!

Redding and Forster both make a press-mounted die that effectively duplicates the in-line Wilson concept. These both have a spring-loaded sleeve that tightly fits the case body. The idea is that the case fully enters this sleeve and is therefore fully supported against movement before the press handle stroke elevates the ram enough for the bullet to engage the seating stem. Much better!

2. Stem Check
Make sure that the tip of the bullet you’re using doesn’t contact the inside of the seating stem! This isn’t as common to see now as it once was. Longer, higher-BC type bullet profiles are prevalent enough that most manufacturers have increased the room inside the stem.

bad seating die stem
Not as common now as it used to be, but here’s what you don’t want! The bullet tip should not contact inside the seating stem.

Certainly, if the tip is bottoming out inside the stem, a few bad things can happen. One is that it’s easily free to tilt the bullet. Two is that the seating depth is then influenced by the tip-to-tip inconsistencies that do exist. Three is that the tip might get damaged in the process. This, by the way, is not nearly exclusively a concern to users of “spikey” bullets. I’ve been running into tip contact created by bullets with more blunt/rounded nosecones, like some of the lighter-weight .308 caliber bullets we’re using in .300 Blackout.

forster custom seating stem
If you’re a Forster user, they can supply a custom-dimensioned stem. I’ve been using these a while now and think it’s a great idea.

There’s more, though. A seating stem that contacts a bullet farther down its nosecone provides more stability during seating. It’s a greater surface area and that is another hedge against the potential for unwanted tilting.

seating stems compared
Contact area is better lower than higher. Here’s a standard stem next to a custom stem.

If you’re a Forster user, they have a custom seating stem option I have been increasingly using. Send a bullet and they’ll custom-made a polished stem that exactly fits it, and in the right place.

3. Start it Right
Can bullets be damaged in seating? Yes. Absolutely. Especially some of the thinner-jacketed bullets can get scuffed during seating, and the stem can leave a ring indentation on the ogive. Some swear that the ring indentation is not hurting accuracy; I say, “I don’t know, but it can’t help.” A stem that’s a little larger inside diameter, that’s also been smoothed to a gentle radius, will make the ring disappear. A good local machinist can help.

Lyman VLD chamfer tool
A more relaxed angle on the inside case neck chamfer eases bullet entry and reduces potential for jacket damage, and is also an asset to getting the bullet started in-line. This is a Lyman VLD tool.

One simple thing that results in a marked decrease in jacket damage is to put a more relaxed inside chamfer on the case mouth. Switching from a 45-degree cutter to one with a 20-degree, for instance, tool angle results in a deeper, smoother chamfer. This also overall reduces entry and seating effort.

Be nice to the bullet!

4. Case Neck Attention
This is related to every other point made so far. The more consistent case neck walls are, the ultimate result is a better centered case mouth, and that results in less chance that seating the bullet is going to try to move the case neck, and also less chance there will be unequal contact as the bullet enters the case neck (less abrasion).

Better concentricity, as said, means the bullet can start straight into the neck and then all the precision alignment built into the tools gets to show its merit.

This is where brass segregation (for wall thickness consistency or runout), outside case neck turning to improve wall thickness consistency, and initial choice on the brand of brass all come in.

Much of that also comes from the choice of sizing die and how well it’s been set up, and that’s been talked on in these pages before (and will be again, no doubt).

And, making sure the case neck cylinders are all the same heights makes a difference too, because that means each bullet is encased in an equal amount of material.

Check out dies at MSSS HERE
Find a chamfer tool HERE
Learn more about custom stems HERE 

The preceding is a specially-adapted excerpt from Glen’s book Top-Grade Ammo. Available HERE at Midsouth Shooters Supply. Visit ZedikerPublishing.com for more information on the book itself, and also free article downloads.

RELOADERS CORNER: Seating Depth Issues

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Don’t take anything for granted! Safety and suitability are both at risk if you don’t take time to analyze and act on this important topic. READ MORE

land illustration

Glen Zediker

As said often, it’s sometimes recent experience that leads to my Reloaders Corner topics. Whether it’s a question I’ve been asked, usually, or, in this case, a malfunction I’ve had, those things are fresh in my mind. I hope to believe, and have to believe, that any such topics aren’t only a question for them, or for me.

That brings us to bullet seating depths, which really means overall cartridge length, using some particular bullet.

Usually, when we’re loading for a rifle with a box magazine, either bolt-action or semi-auto, the cartridge overall length — that’s measured from the base of the case to the tip of the bullet — defines and determines the maximum length. Usually.

What ultimately determines the cartridge overall length maximum, though, is really the first point of contact that the bullet makes (will make) with the rifling or lands ahead of the chamber throat. That space, and therefore overall round length, has a whopping lot to do with the chamber reamer specs, and also the reamer operator’s judgment in some cases, but we need to know.

It also can have a whopping lot to do with the bullet! And that’s what the most of this next is all about.

So here’s the lesson to learn, and, for me, to relearn: Do not assume that if the round fits into the magazine it will be fine. I will, at the least, freely admit to my mistakes because, one, I dang sho should know better, and, two, if I know better and still don’t do better confession is my punishment. Well, not really, but it’s always a wake-up call.

Different bullets have different profiles, different ogive architectures. The ogive is the “curve” beyond the last point up the bullet that’s caliber diameter (meaning full diameter) ending at the bullet tip. My slang but descriptive term for this is “nosecone.” Tracing up this curve, some point will be equal to land diameter. So where this point is on the seated bullet and where this point is ahead of it in the chamber matters a lot.

Unless it’s done as a deliberate tactic, there needs to be some space, some distance between the land diameter point on the bullet nosecone and the lands. The amount of that distance is referred to as “jump,” because that’s descriptive. It’s the gap the bullet has to cross through to engage into the rifling. Usually the closer the better, and that “tactic” used often by precision shooters (mostly long-range and Benchrest competitors) is to purposely seat the bullet so it’s touching the lands. That’s done in the belief that if there’s no jump, then there’s no ill effects from jump. It’s very often right, and I’ve proven that to myself many a time. It’s not always right, but then if it was this all would be too easy.

The reason there needs to be some space is because when a bullet goes from just off to just on the lands, pressure jumps. It’s a “spike,” not a surge, but it’s enough to put a load that’s nearing the edge over the edge. In something like a .223 Rem. it’s about a half-grain-worth of propellant.

hornady 52
Here’s one I messed up with. The ogive or nosecone profile on this bullet is much “higher” than normal for a match bullet of this weight and it encountered the lands at a much shorter overall length than any others I had used. I learned the hard way, even though I already knew better.

So. Here’s the lesson I learned again, but this one wasn’t my fault! Honest! Several years ago, however, here’s one that was my fault: new (to me) match bullet, a short 52-gr. I wanted to try for reduced-course NRA High Power Rifle events. Rifle had a Wylde .223 Rem. chamber. A Wylde has a throat length between a 5.56 NATO and a SAAMI-spec. .223 Rem. That means the throat is fairly much more generous than commercial .223 Rem. specs. The maximum cartridge overall length in an AR15 box magazine is 2.260 inches, and I go 2.255 for a margin. I checked some industry manual data for this bullet and did notice that the overall cartridge length listed in the data spec table was a good deal shorter than that. I quickly did some “math” but without numbers (so it wasn’t really math) and decided that since I had a longer chamber I’d ignore that and just seat the bullets to 2.255. Blew primers right and left.

Back home and gage in hand and, dang, they weren’t kidding! I was about 0.020 into the lands at that cartridge length. That’s a honking lot. That’s also ultimately dangerous because of the free-floating firing pin tapping off the primer when a round is loaded into an AR15. A bullet that’s getting jammed into the lands is greatly more resistant to chambering freely and fully.

I humbly learned my lesson.

Get a gage and use it! The best out there is the Hornady LNL Overall Length gage. This tool lets you very easily find the overall round length that touches the lands with your bullet in your barrel. Very valuable, that.

lnl oal gages
A Hornady LNL OAL Gage will show right quick like and in a hurry with the seating depth that touches the lands is with your bullet in your gun. Valuable!

Use it in conjunction with its companion “bullet length comparator” insert for the very best precision. That tool measures a bullet at a point on its ogive that (usually) corresponds closely with land diameter. It won’t be perfectly the same, but it doesn’t have to be. What matters is that it gives a more accurate figure. Avoiding the bullet tip in a measurement eliminates that (guaranteed, by the way) inconsistency in accurate measurement because of bullet tip variations.

LNL comparator
A “comparator,” like this one from Hornady’s LNL line, is a much more accurate way to measure seating depth because the bullet tip doesn’t get involved. I like the curved one: easier and more accurate by my experience.

Now. To the recent experience: It was with a .300 Blackout (AAC) subsonic. I did not have the means to gauge this using my tools (then, but I do now). However, that wouldn’t have mattered in this case, and why is next.

Tested a factory load. Liked it. Noticed nothing unusual. Functioned perfectly, shot well. Brought it home and filled a magazine, loaded one in the chamber, and set it aside. Folks, just so you don’t think I’m irresponsible, that gun is what I keep at the ready for home-defense. So, my son, who had gone in to unload and then dry-fire the gun, came up and said, “Dad. The bolt won’t open.” Dang. It wouldn’t. I started thinking up all reasons that might be behind that. The bolt carrier would retract a little way, which was the limit of usual “play” in the bolt travel inside it, so I didn’t think anything was broken. To remove the round I pulled off the upper, took it to the shop, and pried back the bolt carrier from the underside. A couple of careful but firm enough strokes and it opened.

The bullet had really jammed into the lands! I mean really jammed. Extracting the round and looking at it, land impressions were clear, and measuring the extracted round showed it was 0.022 longer than the new, un-chambered round. Unseating the jammed round pulled the bullet that far out from the case neck.

I manually inserted another round of the same into the chamber and gave it a nudge-in with my finger, and, sure enough, there it sat not nearly fully into the chamber. Had to tap it back out.

jammed bullet
Here’s the “stuck” round, right, talked over in the article. Land impression is pretty clear, and pretty deep. Notice also that the bullet got pulled out a might upon finally opening the action. On left is the same round out of the same box that was pushed into the chamber; land marks also, just a lot lower!

So. Since it’s a factory load, I really couldn’t have had a clue that it wasn’t compatible with my chamber throat. But now I do. And, for a clue, do that same yourself. If the round won’t drop in and out of a chamber fully and easily, that might be a problem. I still don’t know what the actual measured amount of the excessive length might have been. To find that I’d have to get a box of those bullets and gauge them using the LNL tools. I’m not going to do that. I’ve chosen another load that’s no-issues.

I say “might be” because, again these rounds functioned well, but, also, well, that can’t be good…

I suppose I will now need to start handloading for that contraption. I have also written down 100 times: “I will always check the chamber throat, even if it’s not a long-range rifle…”

Find gages at Midsouth HERE and HERE

The preceding is a specially-adapted excerpt from Glen’s book Top-Grade Ammo. Available HERE at Midsouth Shooters Supply. Visit ZedikerPublishing.com for more information on the book itself, and also free article downloads.

RELOADERS CORNER: Case Trimmers

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An ideal case trimmer provides precision, speed, and affordability. Here are some ideas on avoiding compromise. READ MORE

Hornady Cam-Lok
Hornady Cam-Lock. Good trimmer at a fair price. See it HERE

Glen Zediker

At some point, or points, cases need to be trimmed to a shorter length. Brass flows. Therefore, a case trimmer is pretty much a given in the tool assortment for any handloader.

There are needs and wants, realities and ideals. That’s true with many things, and applies often to reloading equipment. Ideally, a case trimmer will go beyond just trimming the case to a shorter length. They all do that well enough. I think it’s important that a case has a square mouth — dead flat across the top. This is an asset to getting a bullet started well into the case neck during the seating operation.

A Good Trimmer
There are a variety of trimmers available from most of the popular industry tooling suppliers. And most follow a pretty similar form and formula: a little hand-cranked lathe. In these, the back end of the case is chucked into a collet-type fitting. A caliber-size pilot that’s centered in and surrounded by a cutting head goes into the case neck and supports the front of the case.

Not nearly perfect! There are a few reasons and sources for reduced precision. The tool alignment may be true at each “end” of the trimmer, but the case we’re working with probably isn’t true. Mostly, since there has to be a gap for the pilot to freely rotate, and since case neck walls aren’t all consistent in thickness, the fit isn’t close enough to prevent out-of-round rotation. Along with the inevitable case body warp there’s bound to be a tad amount of wiggle. Since the case is supported only at its head area, not by its body, there’s flex afoot.

None of that means the case neck won’t get trimmed to a shorter length, which is the general idea. It does, however, mean that it’s not liable to be perfectly squared up.

LE Wilson
LE Wilson. See it HERE at Midsouth.

A Better Trimmer
I rarely just overtly recommend one tool over all the others, but after a good many years working with case trimmers, I can and will tell you that the LE Wilson design is the best I’ve yet tried. I guess, yes, that is just opinion, but it’s really not.

The difference in this trimmer design is that the case is supported within a sleeve by its body. There’s no polarized suspension front and back. Mostly, there’s no pilot. The cutter on an LE Wilson faces off the front of the case squarely. The sleeve holding the case sit atop a pair of rails and the whole arrangement excludes case condition from the process.

le wilson sleeve
Tap it in… Then tap it out…

le wilson sleeve

So why doesn’t everyone use one? Honestly, I’m not entirely sure. It is a different arrangement, and it’s not cheap, especially not if you accessorize the fool out of it with a stand, a clamping device, and a micrometer. It’s not more than the other higher-end manual trimmers though.

It’s also fast! There’s no clamp-twisting to get the next case in place, and back out again. The sleeves are slightly tapered inside so the case is tapped in and then tapped out. With a little experience it’s amazingly quick to get through your block full of brass.

Flexibility
Virtually all case trimmers can provide additional utility, do different jobs. The cutter can be replaced with a reamer, and some can get reworked into outside case neck turners.

My choice is usually a stand-alone station, and that’s mostly because it’s pretty tedious refitting the appliances. I am, or at least have become, lazy.

forster case trimmer
Forster. This is a good choice especially for those who want to make a multi-purpose tool out of their base unit. There’s a big collection of add-ons that let work over primer pockets, turn case necks, ream case necks, and even hollow-point bullets. Its precision is better than most.
forster accessories
A a few of the things that can go on a Forster. Very versatile tool!

As with all said about alignment for case length trimming, that is also all the same for using a trimmer for other chores. And, yes, I still think the LE Wilson works best as a reamer, for instance, and that is because all the alignment precision is built into the tool itself; the case doesn’t play a role.

About options, by all means fit up a “combo-head” if it’s available that will finish the trim with a nice inside/outside chamfer/deburr. Big time saver. These can be a trick to get set just right, but it sure saves time.

Power
It sure is nice to get a break from the crank! There are, though, as I see it, two kinds of power case trimmers. Those that replace the hand crank with an electric motor and those that are designed from the start to be powered.

Some trimmers offer a means to add your own power source, like an electric screwdriver or drill.

Gracey Match Prep
Gracey Match Prep. Pretty much a big motor! It’s intimidating on first use, but just push the case in and it gets trimmed (and chamfered). It’s way quick in use and produces precise results.

My favorite proprietary power trimmer is a Gracey “Match Prep.” Designed by the late Doyle Gracey as a fast and easy way to trim huge quantities of Lake City brass for NRA High Power Rilfe shooters, it’s a serious machine. It works like a gigantic electric pencil sharpener, at least in spirit. Pick up a case and push it forward into a collar and it’s trimmed and squarely faced. No clamps or sleeves. The case shoulder stops against the inside of the collar, so it’s imperative that all cases are resized prior to use. As said last time, though, that’s really the only time you’ll get consistent results with any trimmer.

gracey holder
A key to a Gracey’s speed is that the cases stop on the case shoulder: just push it it!

I don’t know how many cases I can trim in an hour because I’ve never spent an hour using a Gracey. I can easily do 100 in under 5 minutes.

Another very good power trimmer is the Giraud. Its essential means for and in operation are about the same as Gracey but it is a nicer package with more features. Gracey is pretty daggone simple. That’s not all bad. I’d say Giraud is the best, and its price does reflect that.

One Last
Again, it’s important to evaluate the overall condition of a batch of cases, related to how many uses they’ve had. Having grown a little longer isn’t likely to be the only thing that’s changed in a case that exceeds whatever limit you set for it.

And, speaking of, the “trim-to” length is usually 0.010 inches shorter than the maximum SAAMI-stated overall case dimension.

Next time we’ll look at tools used to treat the trimmed case necks and finish this task in fine style.

Check out some more options at Midsouth HERE

Gracey
Giraud

The preceding is a specially-adapted excerpt from Glen’s book Top-Grade Ammo. Available HERE at Midsouth Shooters Supply. Visit ZedikerPublishing.com for more information on the book itself, and also free article downloads.

RELOADERS CORNER: Case Trimming

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We all have to trim bottleneck cases sometime. Question is when and how much, and then “how,” and here’s a place to start. KEEP READING

case trimmer

Glen Zediker

After going through that last series on keeping up with changes in cases resulting from their use and reuse, “flow” was a culprit behind the majority of detrimental changes. That is: Brass flows during firing. It moves from where it was to somewhere else. Since there’s a finite amount of material in a case, one place is getting thinner and another is getting thicker. The sources of the material, where the flow starts and where it stops, are primarily case necks and case heads.

To completely finish up on all this, the most obvious indication that there’s flow is measuring case lengths from base to mouth.

case trimming
The primary reason to trim is to keep overly-long cases from overrunning their space in the chamber. If the case mouth encounters the end of its allotted space, it can pinch in on the bullet, elevating pressure. Now, there’s usually a good deal of leeway before safety can be a question, but don’t push it…
measure case length
A caliper is the only tool needed to measure case length. It’s not really necessary to measure each and every case each and every time. It’s a whopping lot faster to set the trimmer so it just touches the shortest case you have (revealed through the process itself in setting up the trimmer) and trim all the cases using that setting locked in place.

First, and very (very) important: The ONLY time to check case length, or to trim cases, is after they have been sized! A fired, unsized case will be shorter than it was going in. The reason is because of the expansion in the case that resulted from firing. When the expanded areas are squeezed back to spec by a sizing die the case gets longer as it gets smaller in diameter, same as rolling a ball of modeling clay out on a table. After sizing is also the only time we can we know that the case shoulder area is consistent in dimension.

You’ll see two length figures published for your cartridge of choice: maximum length and trim-to length. Published trim-to length is usually 0.010-inches under what’s listed as maximum.

I got a gage umpteen years ago that could indicate the maximum case length a chamber could accommodate — technically, a “chamber length gage.” Man. I checked the chambers in my main rifles and found that they were all well more generous than the SAAMI-maximum. That didn’t really mean a lot, in fact, to how I proceeded. And it also didn’t mean I can advise ignoring the potential for danger in exceeding SAAMI-maximum. It just pointed out that there are differences in chambers, gun to gun, and at least showed me that not exceeding max stated length should easily keep you safe.

chamber length gage

If a case got too long, exceeded the amount of room given to it in the chamber, that would be a safety problem! The bolt may not close fully. And, if it did, the extra length would create a pinching-in constriction, and that would spike pressure.

We can easily imagine that there’s an influence from relatively longer or shorter case necks in their influence in consistently encasing the bullet. And I’m sure we’d be right. Trimming cases all the same should mean that all the case neck cylinders are the same height. Someone looking to maximize accuracy is liable to get worked up about that enough to trim each firing. I trimmed my tournament cases each use. And, no, none were remotely approaching maximum length. It’s reasonable to further suppose that more or less retention will influence velocity consistency.

Another performance asset may or may not happen, depending on the trimming tool chosen. But. A good trimmer will square the case mouth. I’ve seen a many new cases with a “half-moon” cut after trimming. A square case mouth helps a bullet start and finish straight when it’s seated.

case trimmer
Not all case trimmers are equal. We’ll talk more about some I like next time, and I’ll tell you why.

My routine for this sort of “accuracy-oriented” case trimming is simple — tedious, but simple. I don’t measure each case. I just run them all through a trimmer set to “some” length. Some are trimmed more or less, some just show a bright scuff on one little bit of the case mouth, but they are then all the same length. If I can’t prove it in group sizes, it sho does set my mind at ease that all the cases are holding all the bullets more nearly the same.

For those rifles that aren’t tournament guns, the only concern is that none, indeed, become too long. Those I will check at that “4-firings-in” point. Some may have reached SAAMI-maximum, most won’t have, but all will be longer than when started. I start them at a figure close to suggested “trim-to.” Stop and think about it, and if there’s been overall a 0.010-inch length increase, that’s significant.

As with all things associated with use and reuse in semi-autos compared to bolt-actions, cases are going to grow more and faster in a gas-gun.

Another instance where it’s important to keep up with case lengths, and that, again, really has to do with making them all the same, is for those who crimp (with a conventional cannelure method).

Now, there’s zero harm in using a longer “trim-to” length, and that may be more popular than my method. These lengths are stated in reloading manuals. Keeping up with it over years, I’ve seen no difference in the rate of lengthening trimming longer or shorter; I trim “shorter” solely as a matter of consistency over the (short) life of my semi-auto cases.

Next time more about the tools.

Get started shopping HERE

The preceding is a specially-adapted excerpt from Glen Zediker’s book Top-Grade Ammo.

Glen’s books, Handloading For Competition and Top-Grade Ammo, are available at Midsouth HERE. For more information about other books by Glen, visit ZedikerPublishing.com

Glen’s newest book, America’s Gun: The Practical AR15. Check it out HERE

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RELOADERS CORNER: Four Firings In: Final

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Yikes. Gremlins. Case neck “donuts” are a common development in an aging cartridge case, and it’s often unknown. Read this and know! MORE

case neck donut
Here one is! Or was.

Glen Zediker

Even if the case neck passes the “drop test,” there might be something amiss within that cylinder, and it might not show up until after case sizing, and that is the “dreaded donut.”

What exactly is a case neck donut? It’s a tiny elevated ring of brass on the interior circumference of the case neck, right at the juncture of the case neck, case shoulder. It is pretty much a little o-ring, in effect.

This “tight spot” reduces the case neck inside diameter at that point, which will, not may, have an influence on the amount of constriction surrounding a seated bullet. And since it won’t be perfectly consistent from case to case, accuracy will, not may, suffer.

And, without a doubt, there’s going to be cartridge pressure changes, which can create velocity changes. A donut is not likely to create anything like a pressure spike similar to what an excessively thickened (overall) case neck can, but it can’t be a Good Thing no matter what.

Now. I can’t say this is always a symptom of aging cases (based on the “four firings in” idea I’ve been running with). I’ve seen donuts in new cases. However, in my experience with the brass I normally use, and, therefore, that which I have the most notes on, the formation of a donut seems to coincide at the same time I measure what I think is excessive case neck wall thickening. Again, though, I spent an afternoon at the loading bench with David Tubb trying to solve donut issues he was having after one firing on commonly known “good” brass. We solved them, and more in a bit.

Culprits
There is a difference in the case wall tubing thickness at the case neck, case shoulder juncture. The neck walls are a consistent thickness — it’s a parallel cylinder (or they start off that way). At the shoulder wall thickness increases steadily in a taper as it goes down the case shoulder to then intersect with the case body walls.

There is diverse speculation about exactly what causes or creates the donut. My own experience suggests that there can be more than one factor or influence. But at the root of it is simply this difference in wall thicknesses. The difference has an influence in this area with respect to brass flow. Seems certain that there’s material movement forward from the case shoulder.

If that’s it, then the chamber dimensions (neck diameter and headspace) and cartridge case headspace play their parts. Same old: with respect to case headspace, it’s another reason to set back a shoulder the minimum amount needed for faultless function. Also old news: that’s going to be more for a repeater than a single-shot, and well more for a semi-auto.

I’ve seen it said that the expander ball or sizing button coming back up through a sized case neck “drags” the metal up with it, but also I know without a doubt that sizing without an expander means there’s a more pronounced donut. Checks I’m made sizing with and without an expander (using a neck-bushing-style die), show that an expander or, my preference, an expanding mandrel, reduces the donut influence. That, by the way, is from selecting bushings that produce the same case neck outside diameter with and without the inside neck sizing. I think the expander is just pushing it to the outside… But that’s good!

case neck donut neck turning
This helps! Turning a tiny bit off the start of the shoulder gives some relief in this area and holds off the donut for at least a while.
neck turning cutter angle
The neck turner, however, has to be configured to allow for this. Note the bevel on this cutter.

Fixing It
This one is pretty easy, after a little math at least. The most direct means is using a correctly sized reamer on a likewise correctly sized case neck, and that’s where the math comes in. The reamer should be the diameter of your sized neck inside diameter; that will pare away the donut without changing the case neck wall thickness. The idea is to get the donut without universally thinning the case neck walls, and the reason there is maintaining consistency. That, after all, is why we’re doing any sort of fixing on cases in the first place: get the same performance the maximum number of firings.

Another way, which is primarily preventative, is with an outside case neck turner, if its cutter has an angle or bevel (see photo for example). Turn down onto the case shoulder about 1/16 of an inch. Do this on new cases since that’s the only good time to turn case necks. This area is then “relieved” enough that the donut won’t form, or not for a while. In firing, this thinned area essentially relieves itself. I got this tip from Fred Sinclair eons ago and it’s the only thing I know of that heads off the donut. If you are worried about weakening a case in this area, don’t do it, but I can tell you that’s a moot worry. It’s very common practice among competitive Benchrest and NRA High Power Rifle long-range shooters. That’s how we came to a quick and permanent (well, for the short life of those cases) solution to David Tubb’s donut problems with a 6mm-.284.

neck reamer
This is a “special” reamer, meaning ordered to a custom and specific size. Choose carefully, and it’s an easy fix.

Short aside note that’s being revisited from other articles I’ve done here, but the VERY BEST way to never worry about donuts is to never seat a bullet into this area! That is the reason the better (in my mind) cartridge designs feature long necks.

Glen’s books, Handloading For Competition and Top-Grade Ammo, are available at Midsouth HERE. For more information about other books by Glen, visit ZedikerPublishing.com

Glen’s newest book, America’s Gun: The Practical AR15. Check it out HERE

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RELOADERS CORNER: Choosing Your Brass

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It’s not all the same! Depending on needs and application, there are three decisions that can have an impact on your satisfaction. READ MORE

norma brass

Glen Zediker

Last time I offered a few ideas on loading the same cartridge for use in different rifles. Essential message in that was, in one word, “compromise.” There’s some give and take when we’re trying to please more than one at time, as such is life…

Choosing cartridge cases is a little, to a lot, the same. Different rifles, different action types, different uses, different budgets, all suggest input that helps determine what works best, all around.

There are three things to consider, maybe four.

One is the action type. Semi-autos need “tougher” brass. That, overall, means “harder,” not necessarily thicker. Due to the resizing requirements for good function, which means a little “more” in all areas, there’s likewise more expansion in each subsequent firing. Brass made of harder alloy is less, not more, susceptible to failures — by my experience. Considering the elastic and plastic properties of brass, harder exhibits a little less effect from each.

I prefer harder composition brass for a bolt-gun too. Most NRA High Power shooters do. Reason? It runs better! There’s less “stickiness” in running the bolt for rapid-fire events.

Two: case capacity. They are not nearly all the same! My experience has shown me that more capacity is better, and that’s especially if we’re wanting to edge toward max-pressure loads. Even though the pressure generated inside the case using more (larger case volume) or less (smaller volume) may get to the same level, there is usually more net velocity (at the same pressure) when there’s more room in the case. If it didn’t matter then other things done to expand case capacity (like shoulder angle changes) wouldn’t matter either.

cartridge case capacities
Case capacities vary, and, as you can see, a good deal. These .223 Rem. are each filled with an equal amount of spherical propellant.

Three: Precision standards. What do you expect, what are you willing to do to get it? After enough experience with enough different brands, that is a legit question. Some brass is “better” out of the box. Cost usually reflects on initial quality. Paying a premium for premium quality, which is three things: consistency, consistency, and consistency. That consistency will primarily, or at least measurably, be in wall thicknesses. The choice there is to buy it or make it. That choice is a balance between effort, value of time, and proven results.

lapua brass
Consider first-use or re-use? Good stuff! And you’ll pay for it! Lapua cuts case prep down to sizing: the case heads are milled, the primer pockets and flash hole are reamed. It’s also a little thick and a little soft. Single-shot-style use in a bolt-action, can’t really beat it, but my AR15 Service Rifle beats it to death.

After using enough different brands with varying levels of costs and claims, I think the most honest thing I can tell you is that you’ll likely end up with the overall “best” brass case you can have shopping in the middle, plus a little, and then getting to work on it. A good commercial “name” brand can be made at least effectively close to the dimensional equivalent of a premium brand, like Norma, but it’s not without effort.

Before spending any time weighing or otherwise sorting cases, do all the prep work you plan beforehand. If any prep involves material removal, even trimming, that influences weight accuracy and, therefore, the viability of segregation by same.

Recommendations?
Yes. And no.

About the time you decide there’s some certain way some certain thing is, they up and change it. I avoid making too many lumped-together, generalized statements about particular brands because of that. However! I can tell you that some of the “better” brands of brass also tend not to hold up as well, or won’t if there’s much working load to load (expansion, sizing). I’m thinking here of the better-known European brands, like Norma and Laupua. Those are near about dimensionally flawless out of the box, but they tend to be a little on the thick and soft side. I use Norma in my .22 PPC because the cost is worth it. If I drive from Mississippi to New Mexico to shoot a match, that’s the least of my expense.

nosler brass
This isn’t cheap either, but I have had good results with it. Nosler is, or can be, ready to go out of the box, including case mouth chamfer. It’s held up well for me in semi-autos.

This is also the reason that every serious competitive shooter I know says to buy up as much of one lot as you can, if you know it’s good stuff. That’s for all components.

Sometimes brass chooses you!

As said last time on the “Multiple Gun” loads, if you’re mixing brass things like case volume do factor. As also suggested then, the best solution is to pick a load that’s in around the 80- to 90-percent range of max. I mix brass all the time. I shoot quite a lot of factory ammo and, yes, I save each case we can retrieve. I clean them all, size them all, and fill them with a “compromise” load I worked up for can blasting. The need for those excursions is not quarter-minute precision.

If you’re looking to save as much as you reasonably can and still get “good” cases there’s honestly nothing wrong with Lake City. The more recent production 5.56 measures pretty well, and it’s tough, and relatively high-capacity. I sho can’t vouch for any other headstamp on mil-spec ammo beyond “LC.” However! I suggest purchasing it prepped. Avoid “range dump.” A big issue with once-fired is which chamber it was first-fired in. Avoid .308 Win. (7.62 NATO)! You DO NOT want to deal with M60 or Minigun leftovers.

lc nm brass
This is LC Match 7.62. No primer crimp! For reuse in a semi-auto, it has the right stuff, which means made of the right stuff: it’s hard, tough.

Start HERE on Midsouth. Great deals! Great brass!

Glen’s books, Handloading For Competition and Top-Grade Ammo, are available at Midsouth HERE. For more information about other books by Glen, visit ZedikerPublishing.com

Glen’s newest book, America’s Gun: The Practical AR15. Check it out HERE

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RELOADERS CORNER: Multi-Rifle Loading

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If you shoot the “same” load for different rifles, here’s a few ideas on getting the most out of it for all of them. READ MORE

multigunj reloading

Glen Zediker

I have a few rifles…

Every time I do a new book I have more. This last time around, in writing America’s Gun: The Practical AR15, I built 10 AR15s, and half of those have the “same” chambering (5.56 NATO). My choices that I can case and then uncase any afternoon for some range time might all have the “same” chamber but they’re each and all, in some measured amount, different.

That’s literally in measured amounts, and more in a minute.

If you (like me) really don’t want to load separately, store separately, and use separately, then the only real choice is to employ a “lowest common denominator” tactic. With only one exception, I don’t load uniquely for any of these guns. I pretty much just want a sack-full of ammo at the ready. The one I load uniquely for has a tuned gas system (it’s a practical competition “race gun”).

old and new AR15
Both straight up NATO chambers, but the little one won’t run what the big one will. It’s a gas system architecture difference, and a little more challenge to find a “universal” load. Rifle-length gas systems like on my retro “602” M16 (left) are, by the way, more tolerant of load variations than tricked out short guns like the brand-new USASOC URG-I (right).

Variables
Assuming all the rifles have the “same” chamber, meaning only that the barrel stamp is the same, there still exist differences. There are differences reamer to reamer, and, depending on the operator, there might (will) be differences in headspace, and leade. They’re likely to be tiny, but tiny can matter. Some manifestations of pressure have some to do with the barrel bore (land diameter for instance).

I measure spent cases for all the different rifles. They don’t measure nearly all the same! Of all the set-by-sizing dimensions, cartridge headspace has shown the most variation in my samples.

That, also, is a very important dimension to set. As gone on (and on and on) in RELOADERS CORNER, the idea is to get adequate case shoulder set-back to ensure function, and also to keep it to the minimum necessary to prolong case life. The minimum necessary runs from 0.003 for a semi-auto to 0.001 for a bolt-action.

To set this dimension for multiple rifles that use the same batch of ammo, the means is pretty easy to anticipate: find the gun with the shortest headspace, set the die to set back the case shoulder where it needs to be for that one, and live with it.

If you don’t want to give in thataway, but rather prefer (or at least don’t mind, two technically different outlooks) running multiple dies with multiple adjustments, and keeping the ammo segregated, then here’s more.

I’ve had really good experiences using a turret press. For most rifle needs, one with, say, four spots will allow the use of two sizing dies, maybe three (depending on what occupies the other locations). These dies can be uniquely adjusted for cartridge case headspace. Of course, it’s easily possible to just swap dies in and out but the turret keeps them put and saves a step.

redding t7
A turret press is a sano solution to maintaining differently adjusted dies. Redding and Lyman both make good ones. This is a Redding T7.

If you’re a bolt-gun shooter and have a couple or more rifles that run the same cartridge, and if you’re wanting to get the most from your efforts in loading for each, you might consider this next. Redding has long-made a set of five shellholders with varying heights. They allow a shellholder swap on the same die to alter case headspace, for example. There are also shims available that go under the die lock ring to provide for die body height variance. This sort of setup lets the handloader alter-adjust headspace without readjusting the die.

redding shellholders
Redding Competition Shellholder set. Five shellholders, each 0.002-inches different heights. This allows, for one, different case shoulder set-back using the same die as set.

Levels
Now. As far as lighting on a load that they’ll all shoot their absolute best with. Sorry to say, but “not likely.” There sometimes seems like there is more mystery than there is known in “why some shoot better” with one load. And when I say “load” I’m talking about the dose, the amount of propellant. What that ends up being mandates at least some effort in evaluating more than one rifle when working up to a point you’ll call it “good.”

NATO-spec ammo is hot and getting hotter! I’m talking about true NATO-spec, not just lower-cost ammo sold in a “plain box.” This isn’t about NATO ammo, but it was for me. The difference between pressure levels of NATO and, say, a commercial-made .223 Rem. “match” load are enough that two of the guns won’t even run with that. I set up these guns from the workbench respecting NATO pressures, and that, in most cases, meant firming up the “back end”: heavier buffers and springs.

My good old “do it all” load no longer exists in my current notes. Amazingly, to me at least, it’s up the velocity equivalent of about a grain and a half from what I used to bust up clods and cans with. It’s also a different propellant (now H335).

No question: pressure symptoms must also define the “lowest common denominator” when loading the same for multiple guns. Since I also have to consider reliable function in my own example, and as just suggested, I’m loading up a little nearer the edge. I carefully evaluate spent case condition from each rifle and anything that reads or appears remotely as an excessive pressure sign means I’ll knock a universal half grain off the group load.

The preceding is a specially-adapted excerpt from Glen’s newest book, America’s Gun: The Practical AR15. Check it out HERE

par15

Glen’s books, Handloading For Competition and Top-Grade Ammo, are available at Midsouth HERE. For more information about other books by Glen, visit ZedikerPublishing.com

LINKS
TURRET PRESSES

COMPETITION SHELLHOLDER SET