Witness the creation of the ultimate low-drag, high performance match bullet!
After weeks of teasers, we’re finally able to talk about the new projectile from the folks at Hornady. We actually got to visit Grand Island, Nebraska to tour the facility, and get a first-hand look at the new milled aluminum tipped bullets. This thing is beautiful!
“New to Midsouth Shooters and Hornady, the A-Tip MATCH bullets are the latest and greatest from the Hornady Ballistic Development Group! After years of research, testing, and a new advanced manufacturing process with state-of-the-art quality control measures, Hornady has created an all new Aluminum Tipped projectile. This precision machined tip is longer than polymer tips which moves the center of gravity, thus enhancing inflight stability. The aeroballistically advanced tip design results in tighter groups, and reduced drag variability.”
By using some of the most sophisticated tools in projectile development, Hornady created a bullet with a milled tip, 99% repeatable, and a Doppler Radar verified low-drag coefficient (super-high Ballistic Coefficient) with a winning blend of ogive, tip length, bearing surface, and optimized boat-tail within each caliber.
“We wanted to incorporate aluminum tips in a full line of match bullets for years because we can make longer tips than we can with polymer materials,” said Joe Thielen, Assistant Director of Engineering. “This longer tip is a key component that helps move the center of gravity of the bullet rearward, thus enhancing in-flight stability and reducing dispersion. The problem has always been the cost to produce a tip like this, but we’ve developed a cost-effective process for manufacturing these aluminum tips while staying affordable for serious match shooters. The longer aluminum tips are machined to be caliber-specific, and when coupled with highly refined AMP® bullet jackets, aggressive profiles and optimized boattails, the result is enhanced drag efficiency (high BC) across the board. Each bullet design is carefully crafted for minimal drag variability for the utmost in shot-to-shot consistent downrange accuracy.The materials, design and manufacturing techniques combine for the most consistent and accurate match bullets available.”
Right off the press, the projectiles are sequentially packed, for ultimate consistent performance, from lot to lot, ensuring your projectiles are truly YOURS every step of the way. Think of it like shooting clones of your load every time (100 in each box)! Minimal handling throughout the process means there’s less of a chance of YOUR bullet being marred, scuffed, or altered, which is why each box is packaged with a Polishing Bag for you to give the final buff to your beautiful new projectiles!
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…
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
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.
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.
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.
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.
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
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”).
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.
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.
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.
We also have a link to the Shooters World site here, just in case they update the link before we have a chance to. There’s even a link for European data!
“One of Shooters Worlds biggest goals is to support competitive shooters and reloaders. Shooters World works hard to develop our own load data based on what the competition shooters and reloaders are asking for . Shooters World will always do its best to keep our prices low and Powder available. So once you change to our product there is no need to look anywhere else.” – Shooters World Powders
It may be the single-most influential reloading component, so learn all about it: the primer! READ MORE
This is one component in the collection that might not get all the attention it warrants. That’s because it is the one thing, above all other components, that you don’t want to just swap and switch around.
We’ve all heard cautions about testing new lots of every component, especially propellant, but primers not only change lot to lot, they vary greatly in their influence on any one load, brand to brand. The difference in one brand to the next can equal a good deal more or less pressure, for instance. While there are “general” tendencies respecting the “power” of various-brand primers, always (always) reduce the load (propellant quantity) when switching primers.
This has become more of an issue over the past few years as we’ve faced component shortages. I can tell you without a doubt that going from a WW to a CCI, or from a Remington to a Federal, can have a major influence on a load. I establish that from chronograph readings. No doubt, it’s best to have a good supply of one primer brand and lot that produces good results, and when that’s not possible, it’s a hard sell to convince someone to stop loading ammo and get back to testing. But. It is important. I can tell you that from (bad) experience. How I, and we all, learn most things…
When I switch primers, whether as a test or a necessity, I reduce my load ONE FULL GRAIN. There can be that much effect.
The Thing Itself
A primer is made up of a brass cup filled with explosive compound (lead styphate). Lead styphate detonates on impact. Primers don’t burn – they explode! In the manufacturing process, this compound starts as a liquid. After it’s laid into the cup, and while it’s still wet, a triangular piece or metal (the “anvil”) is set in. When the cup surface is struck by the firing pin, the center collapses, squeezing the explosive compound between the interior of the cup and the anvil. That ignites the compound and sends a flame through the case flash hole, which in turn lights up the propellant.
Primers are dangerous!
Don’t underestimate that. I’ve had one experience that fortunately only created a huge start, but I know others who have had bigger more startling mishaps. These (almost always) come from primer reservoirs, like fill-tubes. Pay close attention when charging up a tube and make sure all the primers are facing the right way, and that you’re not trying to put in “one more” when it’s full! That’s when “it” usually happens. What will happen, by the way, is akin to a small grenade. Static electricity has also been blamed, so keep that in mind.
Sizes and Types
Primers come in two sizes and four types. “Large” and “small”: for example, .223 Rem. takes small, .308 Win. takes large. Then there are pistol and rifle in each size.
Rifle primers and pistol primers are not the same, even though they share common diameters! Rifle primers should have a tougher cup, and, usually, a hotter flash. Never swap rifle for pistol. Now, some practical-style competitive pistol shooters using their very high-pressure loads (like .38 Super Comp) sometimes substitute rifle primers because they’ll “handle” more pressure, but they’ve also tricked up striker power. That’s a specialized need.
Further, some primer brands are available with a “magnum” option. Some aren’t. My experience has been that depends on the “level” of their standard primer. A magnum primer, as you might guess, has a more intense, stouter flash that travels more “deeply” to ignite the larger and more dense powder column. It reaches further, faster.
There’s no real reason not to experiment with “hotter” and “colder” primers, whether the case is stamped “mag” or not. Keep in mind that the experiment is all about the initial flash effect. And keep in mind that this (without a doubt) demands a reduction in the propellant charge at the start.
Over a many years I’ve seen some tendencies respecting flash effect. Using routine cartridges, like .308 Win., single-base extruded propellants tend to shoot well with a cooler spark to start, and the double-base, especially spherical-types, seem to respond best to a hotter flash. Many seem to think that the coating (necessary to form the spherical) and the inherent greater density (less air space between granules) in a spherical demands a little faster start.
Flash consistency is very important, shot to shot. The consistency of every component is important: bullet weights, diameters, case wall thicknesses, and all the way down the list. We’re hoping to get more consistent behavior from a “match” or “benchrest” primer, and we’re paying more for it. I can tell you that some brands that aren’t touted as “match” are already consistent. That all comes from experience: try different primers, just respect the need to initially reduce the load each test. I can also tell you that my notes tell me that the primer has a whopping lot to do with how high or low my velocity deviations plot out.
One last: there are small variations in primer dimensions (heights, diameters) among various brands. These variations are not influential to performance. But! Small diameter variations can influence feeding through priming tools. This can be a hitch especially in some progressive loading machines. Manufacturers usually offer insight (aka: “warnings”) as to which are or aren’t compatible, so find out.
Check out Midsouth products HERE Primer trays HERE
This article is adapted from Glen’s books, Handloading For Competition and Top-Grade Ammo, available at Midsouth HERE. For more information about other books by Glen, visit ZedikerPublishing.com
One of the hottest calibers of 2018, the 224 Valkyrie keeps the hype comings and suppliers are working hard to keep up with customer requests. It continues to impress shooters across the nation, but as it’s popularity gains, more and more people are hungry for better standardized data to build their own ammunition.
Hodgdon Powders, one of the most trusted names in reloading powder, and reloading data, has stepped up to the plate with their amazing reloading web tool, and offered a full menu of reloading data for the 224 Valkyrie. Use this guide to hone your reloads!
Much to the excitement of our Do-It-Yourself customers, the reloading data comes at a time when there are more component options available than ever. You can find everything you need to load your own 224 Valkyrie right here at Midsouth shooters Supply!
Will this wicked new caliber continue to live up to the hype? Have you started reloading for it yet? Tell us your thoughts in the comments!
When a new projectile enters the reloading market, it’s a pretty big deal. It’s always exciting to see innovation coupled with precision, and performance. The GameChanger Bullets, a new offering in the tipped GameKing bullet line, are touted as the “…perfect blend of exceptional Ballistic Coefficients (BC), Accuracy, and Deadly Terminal Performance on tough wild game.” The bullets feature a synthetic tip for smoother chambering, improved flight and better expansion on target (game) impact. The open pocket design below the poly-tip further expands the lead core, while the precisely engineered jacket wall concentricity makes for an incredibly accurate bullet.
Tuned ogive for industry-leading BC.
Boat tail design creates stable flight and accuracy.
Open pocket (Hollow Point) expands lead core instantly on impact.
When it comes to the release of new projectiles, reloading data can be difficult to find. We’ve obtained some load data from the ballisticians at Sierra for select calibers. For more calibers not listed, please contact Sierra for assistance! The load data provided is to be used to their exact specifications.
It’s not always possible to separate guns from loads, and there are some important things to know to get the most from your semi-auto. Here’s one! KEEP READING
I have spent the last couple of segments taking a big step back recollecting my own (early) experiences and education as a handloader. Hope you’re happily indulging me, and hope even more that there’s been some good ideas that have come from it.
I started reloading as a matter of economy, and because I wanted to shoot more. Said then and said again now: if the impetus for reloading is saving money, you really don’t save money! You just get to shoot more for the same cost. Hope that makes sense, and likely you already understand that. Clearly, there are other reasons or focuses that attract folks to handloading, and personalizing ammo performance, improving accuracy, are leading reasons.
I’ve been at least a tad amount (to a lot) biased all along in my department topics toward loading for semi-automatic rifles. That’s been done for a few reasons, and the primary one is that, no question at all, there are specific and important details, a lot of dos and don’ts, in recycling ammo for a self-loader.
This is the reason I’ve been careful to specifically point out the “semi-auto” aspect of any tooling or preparation step. I’d like some feedback from you all with respect to your motivations and applications in handloading. Why do you do it?
Another reason is that, and I know this from much input, as happened with me 45 years ago, my interest in learning to reload came with ownership of a semi-auto that I absolutely loved to shoot! Here of late, my plumber, for a good instance, proudly announced to me outside the local hardware store that he had just purchased his first AR15 and showed me the paper bag full of .223 Rem. cartridges he had just purchased there. A scant few weeks later: “Could you help me get together some tools and show me how to reload?” I did.
Back to the focus, finally (I know) of this topic: what are those differences comparing semi-autos to anything else?
There are a few points, but one of the first, and one of the most important, is component selection. Case, primer, propellant. Propellant first.
I’ll assume, pretty safely, that the semi-auto we’re loading up for is an AR15, or some take on that platform. If so, it will have a “direct impingement” gas system. That’s a pretty simple arrangement whereby the gas pressure needed to operate the system, which cycles the action, is bled off from the barrel bore via a port. From there it goes through a manifold and then into a tube, and then back into the bolt carrier via the bolt carrier key. Gas piston operation is more complex, but what’s said here applies there also respecting propellant selection.
So, it’s kind of a wave. The idea is to get the wave to peak at a point where there’s not excessive gas entering the system, but there is sufficient gas entering the system. Mil-spec. 20-inch AR15 calls for 12,500 psi, for what that’s worth. And “piston” guns are nowhere near immune from concerns about port pressure.
The burning rate of the propellant influences the level of gas pressure at the gas port, and this, easy to understand, is referred to as “port pressure.” The original AR15 rifle gas system component specs (20-inch barrel, port located at 12 inches down the barrel) were created to function just fine and dandy with 12,000 PSI port pressure. Much less than that and there might not be enough soon enough to reliably cycle the works. Much more than that and the operating cycle is accelerated.
Port pressure and chamber pressure are totally separate concerns and only related indirectly.
Rule: slower-burning propellants produce more port pressure than faster-burning propellants. As always, “faster” and “slower” are relative rankings within a variety of suitable choices. The answer to why slower-burning propellants produce higher pressure at the gas port comes with understanding a “pressure-time curve.” A PT curve is a way to chart consumption of propellant, which is producing gas, along with the bullet’s progress down the bore. It’s what pressure, at which point. I think of it as a wave that’s building, cresting, and then dissipating. Slower propellants peak farther down the bore, nearer the gas port. Heavier bullets, regardless of propellant used, also produce higher port pressures because they’re moving slower, allowing for a greater build-up about the time the port is passed.
To really get a handle on all this you have to picture what’s happening as a bullet goes through the barrel in a semi-auto, and keep (always) in mind just how quickly it’s all happening. Milliseconds, less than a few of them, define “too much” or “not enough.” As the bullet passes the gas port, there’s still pressure building behind it, and there’s more pressure building still with a slower propellant. After the bullet exits the muzzle, the pressure doesn’t just instantly go away. There’s pressure latent in the system (all contained in the gas tube and bolt carrier) that’s operating the action.
The symptoms of excessive port pressure come from the consequence of a harder hit delivered too soon, and what amounts to too much daggone gas getting into and through the “back,” the bolt carrier: the action starts to operate too quickly. The case is still a little bit expanded (under pressure) when the bolt starts to unlock and the extractor tugs on the case rim, plus, the increased rush of gas simply cycles the action too quickly. That creates extraction problems and essentially beats up cases. They’ll often show bent rims, excessively blown case shoulders, stretching, and so on.
Getting gas port pressure under control makes for improved function, better spent case condition, and less wear and stress on the gun hisseff.
There’s a huge amount more to talk about on this whole topic, and a good number of ways to get everything working as it should. But. For this, the most a handloader can do, and it’s honestly just about the most influential help, is to stay on the faster side of suitable propellants. Without any doubt at all, there will be rampant disagreement with my advice: no slower than Hodgdon 4895. Most all published data lists propellants from faster to slower, so find H4895 and don’t go below it. That’s conservative, and there are a lot of very high scores shot in NRA High Power Rifle with VARGET and RE-15, but those are edgy, in my experience, and define the very upper (slowness) limit.
That alone doesn’t mean all AR15 architectures will be tamed (carbine-length systems are particularly over-zealous), but it does mean that port pressure will stay lower, an important step.
A caution always about factory ammo: some is loaded for use in bolt-actions (especially hunting ammo(, and might bea very bad choice for your .308 Win. semi-auto. AR15s are actually fairly more flexible in showing clear symptoms, some no doubt due to the buffered operating system and overall mild nature of the .223 Rem. cartridge.
This article is adapted from Glen’s books, Handloading For Competition and Top-Grade Ammo, available at Midsouth HERE. For more information about other books by Glen, visit ZedikerPublishing.com