Tag Archives: improving accuracy

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: Neck-Only Case Sizing

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Neck-only resizing is an option for the bolt-action owner. Here are some ideas on why it works, and when it works best… Keep reading!

winchester bolt action
Neck-only sizing is for bolt-actions ONLY.

Glen Zediker

Cartridge case re-sizing is one of those topics that draws lines and forms camps. I am a big believer in full-length sizing, for any action type or use, and just saying that immediately draws argument.

Before getting into the “whens” and “whys” respecting full-length or neck-only sizing, here’s one that I think is an absolute: cases for reuse in a (any) semi-automatic should be full-length sized; neck-only sizing is only for bolt-actions. Having established that, all this next really only relates to what’s possible with a bolt-gun.

Backing up a bit: a “full-length” sizing die is one that returns the cartridge case body (and shoulder, if adjusted to do so) to near-to-new dimensions. A “neck-only” sizing die doesn’t touch the case body (and may or may not be able to touch the case shoulder). A full-length sizer also sizes the case neck, and, normally, the entire height of the case neck cylinder. A neck-only die can be adjusted to contact the height of the neck cylinder in various amounts.

hornady neck sizer
A neck-only sizing die doesn’t touch the case body, so there’s no reduction in case body diameter. This die can be adjusted to contact the case shoulder, and setting back the shoulder may still be necessary. Make sure you check cartridge case headspace!

The idea behind a neck-only die is to preserve fired case dimensions: make the case a closer mirror of rifle chamber dimensions. One advantage of neck-only sizing comes to those who expect, or need, to get a good many loadings from their cases, since this approach minimizes case stretching on subsequent firings.

However, the primary flag waved by neck-only fans says that it produces the best accuracy, and that full-length sizing is a compromise, favoring function over accuracy. I do and don’t agree, and the rest of this article I hope will clarify what I just said…

The reason I do and don’t agree is that I know folks who cannot get a good group unless they neck-only size, and I know other folks, and I’m one of them, who get very small groups following what many would say is “over-sizing” their cases.

forster neck sizing set
Here’s a nice set for neck-only sizing. The “bump” refers to the capacity to also contact the case shoulder to control its dimension, if wanted.

I believe that the main influence in realizing the virtues of neck-only sizing has a whopping lot to do with the rifle chamber. Specifically, factory-made, off-the-shelf bolt-actions tend to have relatively more generous chamber dimensions, as will many older surplus-sourced rifles. “More generous” is in reference to the tolerances established for the SAAMI blueprint for the cartridge. This is (wisely) done to help ensure that any and all factory ammo will chamber and fire, and also to help ensure general and all-around feeding reliability. Additionally, it’s common to find some (slightly) oval chambers in factory guns; that has a lot to do with the freshness of the tooling when that chamber was cut. It’s even more common to find them that are off-center.

Purpose-built bolt-action competition rifles, such as those constructed for use in NRA High Power Rifle competition, are custom-chambered* and, while few will use what we might call a “tight” chamber, it’s not likely to encounter one on the larger end of acceptable dimensions.
*”Custom,” here, doesn’t mean they are each unique, it just means that they are done by hand employing a precision-made reamer and therefore are what they ought to be, or we sure hope so. And they don’t tend to be overly generous in (any) dimensions.

neck sizing bushings
If you’re going to go, go all in: dies with interchangeable bushings let you control case neck diameter, adding another measure of control, and even less working and re-working of the brass.

So, in the circumstance where we have a chamber that’s a tad amount big and a cartridge case that’s been manufactured to (usually) the smaller end of SAAMI-set standards, that case will endure more expansion, in all directions, than if it had been in a tighter chamber. Sizing only the case neck to accept and retain another bullet, as said, reduces the subsequent expansion that will occur the next firing, but also, and this is likely if there is an accuracy improvement, the otherwise un-sized case might then be sitting more centered in the chamber. And one reason for that is, if the rifle is equipped with a plunger-style ejector (Remington 700 style) that will bear against one edge of the head of the chambered round, pushing the cartridge off-center, askew. (This ultimately creates another undesirable condition, a warp in the case, and we’ll talk about that another time.)

So, a little bigger case returning to a little bigger chamber likely has a little better chance of getting centered, and I truly believe that is why neck-only sizing can be a help to accuracy for a bolt-action. However! A dimensionally-correct case returning to a dimensionally-correct chamber will perform just as well on target. Full-length sizing a case for reuse in a rifle with what I call a “standard” chamber (which is really running a little closer to the minimums established by SAAMI) also makes for good groups. We prove that every High Power Rifle tournament.

Advice: If you notice your bolt-action doesn’t shoot too well with factory loads, neck-only sizing should pay off and is well worth a try. Do, however, make sure to gauge the cases as is often discussed in Reloaders Corner, and, specifically, cartridge case headspace. If the bolt isn’t closing easily, that’s liable to be the culprit right there: shoulder has gotten too tall.

If you’re running a factory bolt-action, by all means try neck-only sizing. If you want to compare results to full-length sizing, just make sure you’re doing that operation right.

david tubb
Now. Don’t go getting the idea that full-length sizing can’t shoot well. Here’s a 1000-yard prone group at the hands of David Tubb, originator of the 6XC cartridge. Tubb sets case shoulders back 0.002 inches, runs 0.004 case neck tension, and full-length resizes using what amounts to a “small-base” die (additional 0.0005-inch reduction at the case head). He’s also not shooting a factory chamber. (Photo note: the yellow pasters were sighters; red pasters indicate record shots).

Check HERE and HERE to get started…

The information in this article is from Glen’s newest book, Top-Grade Ammo, available HERE at Midsouth. Also check HERE for more information about this and other publications from Zediker Publishing.

RELOADERS CORNER: The Value of Accuracy

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Can you take a focus on accuracy too far, or never far enough? Here are some thoughts on why better accuracy (really) matters…

Glen Zediker

dial indicator

Anyone who has ever read one of my books knows the extent of tickiness that can be involved in handloading. Competitive shooters also tend to get pretty wrapped up and sometimes entrenched hopelessly in technical rifle details. All these things we do are done in the hope of better accuracy: smaller shot groups.

Why bother with tickiness? Well, the answer (always) depends on the level of tickiness afoot and on the level of reward we get from it. No other answer makes any sense.

Accuracy always matters. If you do something different or new in the handloading process and see better shot groups, that no doubt was worth it. Ultimately, it was worth it. It might have been upgrading tools, experimenting with components, one or more case prep steps you hadn’t tried before. It’s still always a payback over the expense, time, and effort. But. It’s another level, attaining another level. It’s stepped up. I’ve compared all this to other endeavors where attaining that new level forever eclipses the old. But then there’s also the time and the effort. When I load ammunition, I consider its purpose. I do not turn case necks for ammo that’s going through my old SP1 on a Sunday afternoon of tin can hunting with my sons. For that, I’m interested in volume and function: the best way to load a lot of .223 Rem. with bulk-packed bullets and ball gunpowder, and with the fewest number of steps. We need a lot of ammo because we have eradicated entire species of discarded objects.

But, let’s for the rest of this assume that the sole purpose is the smallest group sizes we can get, day in and day out. That’s easier to talk about and make sense of, because, no doubt, there are factors that influence it, and I do know what they are.

I’ve always judged accuracy by group size. No shock. Most people do it thataway. I’m also way on more concerned with the worst group my combination shows me than I am the best group. Not everyone views that the same. When it gets down to it, though, I want to know what the worst shot I can anticipate might be because that information is very valuable in adjusting for the next shot. Now I’m talking about shooting for score in a tournament.

I picture a circle that outlines the group size I warrant for my rifle/ammo combination. For my own purpose of clarity, I call it “the accuracy cone.” This circle gets bigger the farther I’m shooting. Shots outside that circle need correction, shots inside that probably don’t. Yes, no, I don’t always launch a perfect shot. So honesty matters, objective evaluation of the shot break.

Group ilustration
You are always shooting a group! You might be aiming at one point but you’re shooting a group. The aiming point is really the center of the group. That’s a “zero,” by the way, or that’s how to zero, but this is straying beyond the levee here. This drawing is a representation of the importance of smaller group sizes. One of the biggest helps that great accuracy provides is that it’s clear when there’s need for sight correction, and when there isn’t. The smaller circle the ammo covers on a target face, the more defining sight corrections can be. If that’s not clear: A perfect shot break on a correct sight setting at 600 yards from a 1 MOA combination means that a shot 3 inches left, right, up, or down away from target center is still a “perfect” shot, even though the perforation point was imperfect. With a 1/4 MOA combination, we’re defining “perfect” with more certainty, because “imperfect” is anything outside 1 inch of target center. Follow? This isn’t just theory.

Mathematically-oriented people may tell you (and I understand this) that testing with 3-round groups provides accurate feedback of a round’s performance. It has to do with probabilities and such. However! I believe too much in luck, or as Buddy Dave calls it, “The Bullet Fairy.” Math-folk will further tell you that the more rounds fired the bigger the shot groupings will become. I’ve seen many instances where that wasn’t true, where the first two or three rounds defined the outer edge of what ultimately became a 10-shot group. I can’t argue with math, but I can argue with myself to the point that I want to see more rounds, and more groups, before I cook up a big batch of a component combination and call it good, or call it “match ammo.”

If you are a competitive shooter, better accuracy helps you get all the points you hold for. We can’t, any of us, ask for more than that. If you are a varmint hunter, it means a close miss may become a hit. The smaller the target the more it matters, or the smaller the goal area on a target is. Aim small, miss small. So let’s miss smaller… Examples can continue, and they might involve a trophy elk in New Mexico, or something even more important to stop in its tracks. It’s doesn’t really matter if the target is 10 feet away, or 10 yards, or 1000 yards, a more accurate firearm is a more effective tool. You can’t miss! Or you sure don’t want to.

accuracy cone
This equals that. Accuracy, on-target group size, is a “cone” that gets wider, expands across distance. A 1/2-inch 100 yard gun is not a 5-inch 1000 yard gun. It shoots bigger than that. However! A solid load-test group like this one David Tubb fired at 288 yards held up on down the pike at 1000. Tip: velocity consistency is a key to keeping a group together at extended distances.

LAST WORD
The value of accuracy is undeniable, but the value of time and effort and expense does indeed have a limit. No, I don’t do “everything” possible to my ammo to make it perfect. I have found a few things that really help, things that are reasonably (by my standards) good paybacks. Another tip: Get a good barrel! Honestly: that gets the most from whatever you do, or don’t do, to help the cause.

This article is adapted from Glen’s newest book, Top-Grade Ammo, available at Midsouth HERE. For more information on that and other books by Glen, visit ZedikerPublishing.com