Gavin Gear, of Ultimate Reloader, takes us through an overview of the Forster Co-Ax Quick Change Jaws. Check out the video below!
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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
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.
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 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.
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.
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.
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.
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.
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.
Along with all the other operations we do to them, cartridge cases also need maintenance. A good question is “when”? That’s next… KEEP READING
I tend to write much of what I do for those who reload for production. Those are folks expecting good utility in exchange for the expense and effort: a reliably-performing round of ammunition, over and over again. They’re loading and reloading because they like to shoot. It’s a big bonus to most, and I include myself in this group most of the time, if that good performance comes with a minimum of effort. Clean, size, prime, fill, seat, shoot. Five steps to get to the one thing that matters most: shoot! I am also in another group some of the time, not as often now as I once was, and those folks may add a few more steps before getting to the “shoot” part (case prep mostly).
It would be wonderful if that simple cycle endured without end. But it won’t.
Overall case condition after X-many firings varies A LOT because of a lot of factors, variables. What matters is getting a handle on it. I look over each case each time I load it, but I don’t break out the measuring tools. That’s not neglect. There is never (ever) any excuse for neglect. That’s not what this is about. It’s about working out a responsible, reasonable, and realistic schedule for when to take a close look at the progress in condition that new batch of cartridges cases has followed after some time.
In my experience, which is what’s in my notes, I say that’s 4 firings.
I went through the per-use checks enough times to know the schedule one brand and lot of brass, used with the same loads in the same barrel, follows with respect to changes. And by that I mean when changes require attention. I’m also starting with prepped cases, including trimming, before their first firing.
Let me make clear that I’m not suggesting that 4 firings is maximum case life! What I am suggesting is that this is the point where it’s likely to see measurable influences from use and reuse, and, as such, that it can be measured. That’s what we’re after now: take a check to see what’s happening, and that also is a big help toward getting clues about where and when these changes might get noticeably influential.
So, to be clear: the case has been fired four times, reused three times. Next loading, if there will be one, will be for the fifth use.
Continuing to use and reuse cases, we’re not really using the same cases each time. The cases change, and much of the change comes from material flow, which is brass.
Here’s how it goes, which is to say here’s how it flows: Case neck walls get thicker. The case head area body walls get thinner, over a short span of the body. Primer pockets get shallower and larger diameter. Overall, the alloy hardens over the whole case.
As gone on about a few times in this spot, there’s going to be more change in cases run through a semi-auto than those used in a bolt-action. That’s because of the necessarily additional (comparatively speaking) sizing and also the additional stress resulting from the firing cycle. There’s more flow because the cases are free to expand more.
All case necks expand to whatever the chamber allows. There’s no relationship between that and sized dimension because, clearly, there has to be a small enough neck inside diameter to retain the bullet. It is, though, one of the reasons case necks tend to give up quickest (plus it’s the thinnest-walled area on a case).
The case neck is my primary concern, and the first thing I check. If the walls get too thick it’s possible to cut the space too close between the case neck and the case neck area in the rifle chamber. There might be interference upon bullet release, and that creates excessive pressure, or sure can. All that depends on what the chamber allows for expansion room.
The most simple check is to see if a bullet will freely drop into a fired case neck. If it won’t, stop! Do not reuse that case as-is. A case that won’t pass this no-tool test has excessively thickened.
Somewhere in your notes should be a figure indicating loaded outside case neck diameter, on new brass. This dimension is exclusive of the sized neck diameter, because when the bullet is seated the neck is going to expand to accommodate the bullet. Another check of loaded outside neck diameter will show if there’s been thickening. If an inside neck sizing appliance is used (a sizing button), then that will tell you also, comparing it to what you also recorded for the new case after sizing it. (And it’s a good reason to always run new brass through your sizing die, even if it’s “ready to go” out of the box.)
I hope it’s clear enough why it’s important to “write everything down.” References, standards are big helps.
Direct checks of the neck walls themselves using a suitable tool will show thickening. However! Case necks don’t necessarily thicken the same over the entire height of the case neck cylinder. Remember, the brass is flowing so moves in a direction, and that part of the case has a wave going forward, toward the muzzle. There can and likely will be a tapering from thicker to thinner. Measure at more than one point.
Safety is one thing, and the most important thing, and then the other thing is accuracy. Case neck “tension” needs to be consistent from loading to loading to get reliable accuracy.
Fixing it? An inside case neck reamer is the easiest and most direct means. However! Make double-dang sure you know the numbers and therefore how and at what point to use it! Many are intended for use on fired (not yet resized) necks. Others are a specific dimension that you may or may not be able to specify. Thinning the case neck walls using an outside case neck turner is another direct remedy. A little tedious.
Reamer or turner, though, this job hasn’t finished until the refurbished case has been run through your usual sizing die, and checked again for diameter.
Well, so much for this here and now. Out of room! More next time…
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Knowing, and controlling, this dimension is a crucially important step in the case sizing operation, especially for semi-autos. Here’s what it is and why it matters. Read all about it!
Last time, and to start the new year off, I hit a few highlights on the first of what I think are some of the most important things to understand in reloading for bolt-action and semi-automatic rifles. A majority of those differences is in what’s allowable and possible in cartridge case sizing.
The reason I’m running these articles is to clearly define the differences in, essentially, what you can get away with (and can’t get away without) depending on the action type. Don’t confuse some of the tactics, tools, and techniques used for bolt-actions and (mis)apply them to semis. That can range from frustrating (function issues) to disastrous (blowed-up guns). I hope that these focused articles will clarify the basics before moving on to the finer points respecting each.
Following on that, here’s one: cartridge case headspace. A rifle chamber has a headspace; a cartridge case has a headspace. The second cannot exceed the first. Here’s how it goes:
The area in point is the case shoulder, the area between the bottom of the case neck cylinder and the case body. There are two dimensions associated with case headspace: the diameter of the “datum” line, and the height (measured from the case base) to that line. So, headspace is determined by the location of the datum line. There are only 5 datum diameters in use over the range of bottleneck rifle cartridges. Datum diameter will be indicated in the cartridge description in any good loading manual. (Belted magnums, which headspace off the belt, are the exception, and different stories, and so are rimmed cases.)
Chamber headspace is determined by the chamber reamer and also the one operating the reamer. There are SAAMI standards for all standard cartridges (which are coincidentally those having SAAMI specs). Ammo manufacturers set their cartridge case dimensions to work within those same specs, and almost always with (literally) some room for variations. That means that, usually (and, again, I’m talking about factory-chambered rifles) the cartridge case headspace will be a little shorter than the rifle chamber will accommodate.
When a round fires, as is by now well-known, the case expands in all directions under pressure, swelling and conforming to the chamber, then retracts immediately afterward when pressure dissipates. Since brass has a plastic property, dimensions are not going to return to exactly what they were prior to firing, and that’s what all the sizing tools and operations seek to rectify. So, among other changes, the case shoulder will have “blown forward,” after having snugged up into that area of the rifle chamber. That will have moved the datum line upward. As hit upon last article, semi-automatics are notorious for exhibiting a little more than they “should have” in expanding, and that’s because there’s a little (to a lot) of pressure latent in the case when the bolt starts to unlock and move rearward. This can effectively create additional space for case expansion within the chamber. The case shoulder measurement after firing in a semi-auto might actually exceed that of the actual chamber headspace, or, at the least, be a little taller than it would have been in a bolt-gun having the exact same chamber dimensions. The hotter the load, the more gas system pressure, the more this might show.
To be rechambered, this case has to have its case shoulder “set back,” which means that the sizing die has to contact the shoulder area enough to budge it, bump it, down to a tolerable height. Here next is how to find out what that “tolerable” height is.
The process of adjusting a sizing die to produce correct cartridge case headspace is plenty simple and easy, and requires a specialty tool (and you knew that was coming): a gage to determine datum line height.
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First, and important: this has to be done on the first firing of a new case, either a factory-loaded round or your own creation. For more conclusive accuracy, measure 4-6 cases, and, very important: de-prime a case before taking a read (the primer might interfere).
Measure a new case. Write that down.
Measure your fired case. Write that down.
Again, in a semi-auto the chamber might not actually be as long as the fired case reading says it is. In a bolt-gun, the post-firing case headspace dimension is going to be a closely-accurate indicator of the chamber headspace (but always subtract 0.001 inches from any reading to account for the predictable “spring back” in brass).
To set the die, take the fired case reading and reduce it. How much set back? I recommend 0.003-0.004 inches for something like an AR15 or M1A. That’s playing it safe, considering, again (and again) that there may likely have been additional expansion beyond chamber dimensions. I’d like to see folks set back their bolt-guns at least 0.001, but I’m not going to argue! I don’t like running sticky bolts.
A little extra space ahead of the case shoulder helps ensure safe and reliable functioning in a semi-auto, and also, importantly, reduces the chance that the case might bottom out on the shoulder area in the chamber before the bolt is fully locked down. Firing residue in a semi-auto chamber is also effectively reducing chamber headspace, and that’s another reason for the little extra shoulder set-back. Keep the chamber clean!
Why not just set the shoulder back, for either action type, to what the factory set for the new case? Doing that really wouldn’t affect load performance, but, in my belief, deliberately creating what amounts to excessive headspace is not wise. It’s just that much more expansion, that much more “working” that the brass has to endure, that much shorter serviceable brass life. However! That’s not nearly as bad as leaving the shoulder too high! That’s dangerous.
Do you have to do this with a bolt-gun? I say yes, but freely admit that, at the least, from zero to “just a tic” is safe enough. What you do need to do is know what you’re getting! For a bolt-action it is possible, and some think wise, to determine the necessary case shoulder set-back based on what is needed to close the bolt on the resized case: adjust the die down a tad at a time until the bolt closes. Depending on how stout the load is, it might be 2-4, or more, firings before the shoulder needs to be set back for a bolt-gun. But, rest assured, it eventually will. Just keep up with it. I think the bolt should close easily (and if you’re having issues with that in your handloads, there’s the first place to look for a cure). It’s really not possible to follow this plan with a semi-auto because the bolt will close with much greater force during actual firing.
It’s easily possible to improve the alignment and concentricity of a die set, and the result is getting closer to perfection in your ammo. Here’s how…
Last time I wrote about some problems some dies can have. A couple of those things mentioned had a thing or two to do with preparation and setup, and I said then that “next time” I’d address a few ways to improve the results from the dies you already have. So here it is, sizing die first:
Many of the parts that make up a die, including the die body itself, have threaded couplings to allow for adjustment. Well, threads have gaps and that means there’s some amount of free movement afoot, or “afloat” more correctly. If there were no gaps between threaded surfaces then there would be no threading possible. To see it, loosen a locking or jam nut from a die part, the seating die or decapping stem for instance, and wiggle the part. It wiggles… Taking steps to, at the same time, take out that play and improve parts alignment pays off.
ONE: Let the shellholder float. One of the easiest mods to make to improve all die ops is to remove the apparatus that secures the shellholder into the press ram. It’s usually a wire spring clip. Pliers get it gone. Now the shellholder is free to slip in and out, mostly out, of its slot in the press ram, and an appropriately-sized O-ring banded around the slot area keeps it secure. Head to a real hardware store and find one easy enough. This mod has done two things: one is that the spring clip usually cocks the shellholder so it’s not sitting flat and flush with the ram top, which means neither is the case it’s holding, so now it is; and, two, there is now a self-centering action since the shellholder is free to move a tad. Always keep in mind that we’re dealing with small “tads” (0.001s of inches) and even though it might not be visibly noticeable, this floating setup will result in better alignment.
TWO: Flatten the die lock ring. The next little help is to get the die body and press ram as closely aligned as we can. There’s a lot of gap resultant from the helix of 14-pitch threads. After adjusting the die body downward to produce the amount of case shoulder set-back you want, run a case fully into the die and, holding pressure (lightly, not forcibly) down against the press handle, secure the locking ring. This will ensure that the die is sitting “flat” atop the press. Then ONLY install and remove the die using the locking ring itself! Never the die body. By the way, and this actually is important: I don’t like lock rings that secure via a set screw; I prefer those that offer a clamping-style effect. The little set screw will lever against the angled threads on the die body and that, alone, can tilt the lock ring.
If you’re using a standard-form full-length sizing die, it will have an expander ball or sizing button (either term applies the same, just varies with who’s literature you’re reading). This part is mounted to the decapping stem and functions to open up the inside case neck after the case neck has been outside-sized by the die interior area. Depending on the difference in diameters between the newly-sized case neck inside diameter and the sizing button diameter, that’s more or less stress and friction the neck endures.
I’ve talked more than a few times about the value of polishing the expander to reduce friction, but you still need then to make sure it’s sitting dead center within the die. So…
THREE: Align the expander ball. There’s a little bit of “feel” involved in this step, but it’s not hard to develop. The idea is to tighten the locking screw that secures the decapping stem against movement while the expander ball is captive in the sized case neck. After adjusting stem height (and, by the way, noticing the relatively huge amount of free movement the stem has) run a case up fully into the die and then retract it until you feel the expander engage within the case neck. Stop there. Now apply a little pressure against the press handle going the other direction (as if running the case back up) as you tighten the lock ring on the expander stem. That just set the expander in the center. If you have the tooling to determine this, select a case that represents your better examples of case neck wall thickness consistency for ultimate results.
Moving to the “other” die, the seater, the first step is the same as for the sizing die: flatten its seat atop the press, and that’s done pretty much in the same as for the sizing die. Instead of running a case into the die, though, I set an adequate number of flat washers atop the shellholder to bear some pressure against the die bottom. Then…
FOUR: Center the seater stem. Just like with the decapping stem, there’s thread play in the seating stem. Move the stem more toward an aligned center by simply securing its lock nut when there’s a bullet bearing up against the seating plug. As said, select a case with consistent neck walls to get best results. Now. The only foible with this is when you change seating depths by threading the stem up or down. It’s easy enough to repeat this op-step, but remember to do it. The BEST defense against alignment issues is purchase and use of a “competition”- or “benchrest”-style seating die. I’m talking about those having a spring-loaded sleeve that accepts the case fully before being run up to engage the seating plug. But, those still need to have their seating plug centered following the same sort of process used in these other “tricks”: snug the lock over a little pressure. That only has to be done once, though, for this die type.
Accuracy matters! Now here’s what matters to accuracy… This article discusses 5 essential steps that pay off big.
Last time I wrote a little “essay” on the importance of accuracy and a few ideas on why it matters and how to judge it. That’s all well and good, but the part I knowingly left out was to say more about “how” to get the most of it. Here’s a few points that, over a many-many years, have proven themselves to me to improve the quality of on-target perforations, and, to make sure I’m clear, that is manifested by smaller-diameter shot groups. There are a plenty of others who agree with these tips. There are plenty of others who might not agree with all of it, and even a few more who would love to add their own “can’t miss” components to this mix. But here are mine.
ONE: After-the-fact concentricity. By that I mean actually checking loaded rounds on a runout indicator. Concentricity is pretty much the goal for sizing, seating, and neck-related case-prep steps, like outside case neck turning. However! All those things are done to help support concentricity, but not a one of them is concentricity.
Concentricty is the centered relationship of all influential circles in a cartridge case, with the reason that a more concentric round will have its bullet looking down dead center into the rifle bore: ultimately, if the loaded round spins “flat-line” it will shoot better than those that don’t.
It starts with brass selection and then likely also segregation. Then it moves on to the quality of tool alignment.
I have checked enough factory-loaded rounds though a concentricity fixture, and those that show the best group the best; even if the overall group from random selections is so-so, “flatliners” shoot smaller.
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TWO: Inside flash hole deburring. I know I’ve mentioned this before, but this simple and easy step shows up on target next firing on thusly-prepped cases. It improves propellant ignition consistency and, depending on the tool used, also ignition efficiency.
There’s a burr inside most cases that resulted from manufacture (with only a few drill-cut exceptions, like Lapua, cartridge case manufacturers punch the flash hole). This burr is variable in size and scope, but it acts as a block to the spread of primer flash, and it’s redirecting or misdirecting the flash at the same time.
It only has to be done once. Ever.
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THREE: Primer pocket uniforming. This helps because it lets you set each primer the same, and also fully. The reason is that it squares the “edges” or corners of what otherwise is a slightly bowl-shaped cylinder. A perfectly seated primer is sitting square and flush on the bottom of the pocket, with its anvil legs compressed. This “loads” the compound for rapid and consistent ignition. If the primer isn’t seated fully then the firing pin finishes that job before detonation. That creates what equate to time variables — inefficiency.
Funny, but clean primer pockets don’t shoot any better than dirty pockets. What matters is flat pockets.
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FOUR: Consistent case sizing. There is a widespread fear, especially among some “accuracy” fanatics, about sizing ops. There’s also a lot misunderstood about full-length sizing versus neck-only sizing and so on. But. What matters is that, whichever tooling and how much sizing the cases are treated to, it needs to produce dead-same cases. Consistent case expansion dynamics is not often talked about, but it’s influential, especially on longer-range rounds. Just in general, going a little on the “light” side with sizing might seem like a good idea (less stress, less working the metal, etc.) but it can also lead to round-to-round inconsistencies. My belief is that it’s better to be more “positive” in sizing ops, and by that I mean to reduce a case neck 0.003 inches rather than 0.001 prior to seating a bullet. Get all the case shoulders the same height. Running extra-light case neck tension and leaving case shoulders where they emerged last firing may not reproduce round-to-round consistency, unless the rifle chamber was perfect and the cases were too. A little more sizing works the best for the most of us in the most rifles.
FIVE: Invest in a good seating die. No doubt: the bullet seating operation is the “last thing” that happens and it’s also the one thing that can corrupt the care and treatment given to the quality of the loaded round prior. A sleeve-style seater, well machined, goes a whopping long ways toward preserving alignment, and, therefore, concentricity. Also make sure that the stem in yours comes to rest well down onto the bullet ogive, and, above all else, is not contacting the bullet tip! That will wreck a round.
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