Two things happen every spring in Lake Charles, LA which shouldn’t be missed: The wonderful folks at Choupique Crawfish start up the giant boiler, and serve pounds upon pounds of delicious crawfish, and The Midsouth Shooters Crawfish Cup prepares the Action Pistol competitors for another year of excitement.
There’s nothing in this world quite like gathering around a newspaper-covered table, and dumping a huge pile of boiled crawfish, potatoes, onions, and sausage. You get to break bread with friends and family, throw most of your good manners to the wind, and enjoy.
the 2018 Crawfish Cup carries the same essence as the communal table. We gather, hungry for the competition. We trade stories of past victories, or near losses. We remember those who can’t be with us. Most importantly, the family comes together to share in a special event.
The event itself is a will be held on April 27th and 28th. It’s a prelude to Bianchi Cup, where the best of the best come to compete, hone their skills, and get in the Action Pistol mindset; the Zen Trigger Mode. What makes the Crawfish Cup unique? It’s not just elite competitors like Doug Koenig, Julie Golub, and Bruce Piatt! It’s novices, it’s intermediates, and it’s professional shooters like Midsouth Shooter Kevin Angstadt! It’s a great place for those new to the discipline to learn from the best in Action Pistol. It’s a place where all pretenses are dropped, and the competition brings everyone together, on a level playing field.
We’re excited to travel back to Lake Charles, and we hope you’re ready to join us for some of the best Action Pistol events in 2018. Make sure to follow all the action on the Crawfish Cup Facebook, Twitter, and Instagram.
Ballistic coefficient is a term that’s often used but sometimes not fully understood. Keep reading to find out exactly what it is, and what it isn’t…. HERE
A “ballistic coefficient,” or “BC,” is a number that suggests a bullet’s aerodynamic performance.
BC is a component in bullet design that matters much, and it matters more the farther it travels. Bullets that flat out fly, fly flat far out, are of great interest to any longer-range shooter. A bullet with a high(er)-BC is also an advantage at shorter distances, especially when there are variations in the shooting distance. A flatter-shooting (one of the traits supported by a higher BC) bullet means a more flexible zero, a smaller difference in the elevation hold from, say, 100 to 300 yards. BC is influenced by sectional density, bullet weight, and, mostly, its shape or profile.
BCs are derived by comparison. Here’s how that works: There are “standard” bullets that are mathematical models. Bullet designers and ballisticians know which model to apply to different bullet styles. Pistol bullets, for instance, are calculated from (compared to) different models. For the majority of rifle bullets we’ll encounter, one common model is a “G1” (there are others, like 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 doesn’t exist in a tangible sense.
The standard bullet has a BC of 1.000. An actual bullet that’s compared to, for example, the G1 at points, distances downrange, will either be flying faster or slower than the G1 model. If it’s faster, its BC will be greater than 1.000; if it’s slower, it will be less than 1.000. So it’s a percentage of the standard or model bullet’s performance.
Comparing bullets with different BCs, the one with the higher number loses less speed over distance. Losing less speed means its flight time will be shorter and it won’t drift and drop as much as will a bullet with a lower BC. So, a 0.600 flies better than a 0.550.
Depending on the bullet-maker, assigned or published BCs are either calculated or measured. More mathematics than I can wrap my mind around can get these calculations done based on a blueprint. Measured BCs involve chronographing at the muzzle and then at other points on downrange, same bullet, same flight.
Which method — math or measure — provides the best information? Some, and this only “makes sense,” believe that a measured, tested BC is more realistic and, therefore, more valuable. But, if the point is to compare bullets, calculated BCs might be more reliably accurate. I know a number of very serious NRA High Power shooters who have gone to great lengths to “field test” different bullets. It’s not easy to chronograph at long range. Given that information, measured BCs are quite often lower, but not nearly always. Reasons follow.
All the drift and drop tables (whether printed or digital) you’ll see are based on a bullet’s assigned BC. The accuracy of those tables clearly revolves around what the actual, at that moment, BC performance is from the bullet you’re shooting. Also, some bullets have a different stated BC based on muzzle velocity to start.
A whopping lot of things affect the actual, demonstrated BC: anything that can influence bullet flight influences the actual BC performance.
Bullet stability is 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 BC outcome.
Atmospherics, which add up as a list of factors, influence BC mightily. 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 BC as do any conditions that serve to hinder its flight. BCs are based on sea-level so can easily show as a higher number at a higher elevation.
Range-realized 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. If you’re interested, there’s some valuable information from David Tubb (visit DavidTubb.com). He’s done a volume of work on calculating influences from atmospherics as it applies to his DTR project, which, in one way of seeing it, gets down to understanding why it’s really rare to dial in what a ballistics table says for a particular bullet and speed and distance, and hit the target.
One last (for now) bit of information I’ve always found valuable: a BC is a finite thing in one regard, and that is that any BC derived from a G1 model, for instance, fits all bullets with that same BC. This was helpful before ballistics apps were as common and easy as they are now. For instance, if there was a new .224-caliber bullet with an advertised BC, but no tables, just find another bullet, of any caliber, with that same BC, plug in the velocity, and the drift and drop figures will be accurate.
The information in this article is from Glen’s newest book, Top-Grade Ammo, available HEREat Midsouth. Also check HEREfor more information about this and other publications from Zediker Publishing.
New for 2018, a proven self-defense handgun load gets a performance boost! Read all about it HERE
Federal Premium Ammunition announced a new high-performance self-defense load: Hydra-Shok Deep. This new offering builds off the time-tested Hydra-Shok platform with design improvements that better meet modern performance measurements. Shipments are being delivered to dealers.
Federal Premium Hydra-Shok ammunition has proven itself for self-defense since 1989. Hydra-Shok Deep’s redesigned bullet features a more robust center post and a core design that provides as much as 50 percent deeper penetration than classic Hydra-Shok.
Larry Head, director and chief engineer of handgun ammunition: “Hydra-Shok Deep offers consumers a round that results in consistent, reliable performance through typical defensive barriers and penetrates to the depth deemed optimum by the leading law-enforcement agency in the United States.”
Hydra-Shok has been a self-defense staple since its debut in 1989. At that time, the FBI had requested a projectile with better terminal ballistics than traditional cup-and-core bullets, and Federal responded with Hydra-Shok, which uses an expanding bullet with a notched jacket, non-bonded lead core and unique center-post hollow-point design. That provided better penetration and more consistent threat-stopping expansion than other bullets at the time.
The new Hydra-Shok Deep bullet features a core design that provides up to 50 percent deeper penetration than original Hydra-Shok and similar loads from competitors, and the center post has been improved so it’s more robust, which provides better integrity and performance through barriers. Testing shows that Hydra-Shok Deep penetrates 15 inches in bare ballistics gelatin, which is the optimal depth, according to FBI standards.
“The primary goal of Hydra-Shok Deep was to penetrate to the FBI’s optimum depth of 14 to 16 inches and at the same time provide more consistent performance though the intermediate barriers,” Head said. “We also wanted to develop a round that would score significantly better through the FBI protocol testing than standard Hydra-Shok. Hydra-Shok Deep does all of this with a 70-percent improvement in FBI protocol score.”
Although the bullet’s performance in ballistic gelatin is impressive, many shooters might wonder how Hydra-Shok Deep will boost their real-world performance. Head explained why the remarkable improvements in expansion, penetration and integrity through defensive barriers are especially important to self-defense.
Hydra-Shok Deep will initially be offered in a 135-grain 9mm Luger, with other loads coming soon.
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.
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.
NOTE: Bolt-Gun Only! 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.
The information in this article is from Glen’s newest book, Top-Grade Ammo, available HEREat Midsouth. Also check HEREfor more information about this and other publications from Zediker Publishing.
Correct primer ignition is a key to consistent velocities and good accuracy, and maybe even survival! Let’s make sure the primer pops proper. Read how…
Last two times we’ve looked at the tools and process of seating primers and also the thing itself. This time let’s take it another step and perfect the important step of priming a centerfire case.
As gone on about in the first article, it’s very important to seat each and every primer flush to the bottom of the cartridge case priming pocket. Tool choice has a whopping lot to do with how well attaining that goal can be reached, and that’s because it is a “feel” operation.
However! Probably the biggest asset to correct primer seating is a primer pocket that’s correctly dimensioned and correctly finished. And this, in effect, removes some of the importance or contribution of the “feel” needed and that’s because when the primer stops it will stop flat and flush. If the pocket is what it should be.
With the exception of a very few (and expensive) cases, the primer flash hole and the primer pocket itself are punched, not drilled and milled. That’s done, of course, in the interest of efficiency in producing the case. That manufacturing process, though, hain’t perfect.
Cross-section a case head and you’ll see that the inside bottom of the pocket is a little bowl-shaped; the corners aren’t square, which means the bottom of the pocket isn’t flat all across. Since the bottom of a primer cup is indeed flat, it’s way on better if these surfaces are a match.
A “primer pocket uniformer” fixes this to the same level it would be had it been machined: it will be at “blueprint” specs. A uniforming tool also sets pocket depth and will correct a shallow pocket. And again, the flat primer cup mated with an equally flat primer pocket bottom results in a truly well-seated primer.
In my estimation, I think this is an even more important procedure or preparation step for those using any automated or semi-automated priming process, such as encountered on a progressive-style press than it is for “precision” handloaders. In short: the less feel in the tool that’s available to guide you to know the primer has seated completely is offset a whopping lot by the assurance that flat-to-flat flush contact results pretty much just from running the press handle fully.
It’s another step, though, that adds time and tedium to the reloading process. Add power and it’s a lot easier, and, for the majority, has only to be done once. True, after enough firings a pocket will get shallower, and it will also be getting larger in diameter. Usually the increased diameter outruns the loss of depth in signaling the end of case life.
I use mine in place of a primer pocket cleaning tool. There is zero harm in running a uniformer each use for reloading. Uniformers are available as fixed- and adjustable-depth. I generally recommend getting a fixed tool, and then trusting it. Setting depth on an adjustable model is tedious, and critical. Too deep can weaken the case.
If you’re wanting to load once-fired mil-spec cases, or have to load once-fired mil-spec cases, then the original primer crimp must be removed. A primer crimp is small lip of brass that’s pinched into the primer edge during the primer seating process. It holds the primer in place against inertia-induced movement that might unseat it. Now, you never ever need to worry about crimping your own ammunition. All that matters to us is removing the excess brass residual from the original crimp. The most simple, and fastest, way is using a primer pocket swaging tool. These are either press-mounted or stand-alone stations. Just run it, run it out, and the pocket has been swaged to unimpeded roundness again. It is possible to use a uniformer to remove crimp, but it’s a tool for another job and, almost always, it’s best to use specific tools for specific jobs. It’s a difficult chore with a uniformer, and the uniformer also may not smooth the entryway adequately.
Overall, get a swager and keep it simple. They’re not expensive, they’re easy to use, and, as with other such processes, has only to be done once for the life of that case. After swaging, by all means run a uniformer if wanted.
Should primer pockets be cleaned? Why not… There is probably no influence on accuracy if the pocket is dirty or spotless, but, why not… Deprime prior to case cleaning to get that area treated. I preach heavily on the virtues of a stand-along decapping station to keep grit out of the sizing die. A primer pocket cleaner is fast and easy to use, but, as mentioned, I instead just run a uniforming tool in its place.
As said a few times in this series, the most important thing is to know that the primers (all of them) have seated to at least slightly below flush with the case base. Just seeing that does, in no way, mean each primer is seated to perfection. There are variances in (un-uniformed) primer pocket depths. At the least, one more time, uniformed pockets will or sure should take a big step toward providing more certainty.
A “high” primer, one that’s not seated fully to the bottom of its pocket, results in a “soft” strike from the firing pin, and that’s because some of the inertia/energy in the speeding pin is siphoned away because it first will fully seat the primer… However! There’s another, even more important reason all primers should be seated fully: When used with a rifle having a floating-style firing pin, which is an AR15, the normal and unavoidable inertia-induced firing pin movement upon bolt closing will result in the firing pin tip contacting the primer. It will bounce or tap off the primer. If the primer is sitting out farther, there’s a greater likelihood of setting off the cap. That’s called a “slam-fire” and its aftermath ranges from shaken nerves to shrapnel infestations about the facial area.
Last time the tooling and process of seating a primer got detailed, and now more details about The Thing Itself. Read all about it…
A primer consists of a brass (usually) cup filled with impact-detonated explosive compound, lead styphate specifically. Right. Primers explode. The compound starts as liquid, not that that matters, and while it’s still wet, a triangular metal piece called an “anvil” is positioned in the opening. When it’s hit by the firing pin, the center of the cup collapses, squeezing the explosive compound between the interior of the cup and the anvil. That ignites the compound and shoots a flame through the flash hole. That ignites the propellant.
There are two primer sizes, and then type variations. The two sizes are “small” and “large.” For example, .223 Rem. uses small, .308 Win. uses large. Rifle primers and pistol primers are not the same, even though they have diameters in common. Rifle primers have a tougher cup, and, usually, provide a hotter flash. Do not substitute pistol primers for rifle primers! Some pistol shooters using very high-pressure loads substitute rifle primers, but also often need to increase striker impact power.
Variations: There are small variations in primer dimensions, heights and diameters, and also variations exist in new-case primer pocket dimensions, among various brands, and, of course, lot-to-lot variations can and do exist within any one brand. Usually, these variations are not influential to suitability. Usually. However! On occasion, small diameter variations can affect how well different primers will feed through various make priming apparatus. This can and has become a hitch in some progressive loading machines. Cup height variations can lead to seating depth (primer height) issues.
There are also “magnum” primers. These have a hotter spark. They are engineered to deliver a stouter kick-off to larger, more dense columns of slower-burning propellant. They also work well with spherical-type propellants (less air space between the granules). There are also “match” primers. These ostensibly are more consistent quality. Not all manufacturers offer these options. If they do, unless you have a scheme or more carefully-considered reason, just go with what fits your application. There’s no need for match primers in blasting ammo. There are, no doubt (and no doubt significant) differences among varying brand primers with respect to “output.” As mentioned earlier on, there are also pretty well-known tendencies that are either more or less preferable among varying primer brands.
The primer is, in my experience, the greatest variable that can change the performance of a load combination, which is mostly to say “pressure.” Never (never ever) switch primer brands without backing off the propellant charge and proving to yourself how far to take it back up, or to even back it off more. Don’t deny this one.
I back off one full grain of propellant to try a different primer brand.
Finding the best-performing primer for any particular combination of cartridge, bullet, and propellant isn’t just always as easy as putting a “match” primer in there. I have my preference, and it’s what I try first, but, to be certain, sometimes best accuracy and consistency (related) come with another. Again, it’s a combination of propellant fill volume, burning rate, propellant type (single-base, double-base, extruded, or spherical), and column “packing” density that favors either a “hotter” or “cooler” flash.
Priming cup composition also factors mightily in my final choice, and that’s a big factor in some semi-autos. More next time.
SAFETY Do be extra careful handling primers! No kidding. It’s the most explosive element in a cartridge, and it’s intended to be detonated from impact, so… Wearing safety glasses at the loading bench might seem nerdy, but it’s wise. Likewise, and this has happened way on more than once, but, fortunately, never yet to me, is a mass detonation of primers contained in a feeding device, such as a primer feeding magazine tube. Such circumstance is grave indeed. Progressive loading machines, as well as many bench-mounted appliances, use a tube magazine that contains the primers. This tube must be filled, like any magazine. Make sure you know when full is full, and don’t try to poke in one more. This is usually when “it” happens. Remember, primers are detonated via pressure. Said before, but important enough to say again now: Never (ever) attempt to more deeply seat a primer on a loaded round. And keep the priming cup (the tool part that holds the primer for seating) clear of all debris. I’ve heard tell of brass shavings, leftover tumbling media, and the like, getting between the primer and the tool cup, and forming its own little firing pin.
Hornady has just announced their new products for 2018, from the much anticipated new reloading tools, to innovations in ammo and projectiles, Midsouth is eager to fill our shelves with their new offerings! Read on for a brief breakdown of what’s coming soon!
New in Reloading:
Cordless Vibratory Powder Trickler:
Some cool tools are on their way from Hornady MFG., like this Vibratory Trickler, which makes “quick work of various reloading chores!”
The Vibratory Trickler, powered by two AAA batteries, features variable settings to trickle all kinds of powders, ensuring the precise amount for each charge. Its modular design means you can use it with or without the base and also makes cleanup quick and easy.
Trickles all powders
Light-up LED screen
High, low, and variable trickle settings
Use in base or outside of base
Weighted for stability
Hornady Rotary Case Tumbler:
Clean and polish brass cartridge cases to a brilliant shine with the rotary action of this tumbler, coupled with its steel pin tumbling media (included). Use in conjunction with Hornady® One Shot® Sonic Clean Solution.
Six-liter drum holds 5 pounds of brass cases. Set tumbler to run for up to eight hours in half-hour increments using the digital timer.
Check out all the new items coming to our reloading category by clicking here!
Speaking of reloading, lets take a look at some of the new projectiles being developed by Hornady!
The DGX® Bonded (Dangerous Game™ eXpanding) bullet features a copper-clad steel jacket bonded to a lead core to provide limited, controlled expansion with deep penetration and high weight retention. Bonding the jacket to the core prevents separation from high-energy impact on tough material like bone, ensuring the bullet stays together for deep expansion.
DGX® Bonded bullets are built to the same profile as the corresponding DGS® (Dangerous Game™ Solid) bullets but expand to 1½ to 2 times their bullet diameter.
The thicker 0.098” copper-clad steel jacket of DGX Bonded sets it apart from other dangerous game bullets, allowing it to tear through tough material like hide, muscle and bone.
DGX Bonded features a flat nose with serrated sections to deliver a uniform expansion from 100 to 150 yards and straight penetration, reducing possible deflections.
Bonded Jacket and Core
The bonding process locks the jacket and lead core together, improving the retained weight of the expanded bullet.
ELD-X and ELD Match Bullets:
There’s also a few new calibers coming to the ELD-X line of projectiles. The Extremely Low Drag – eXpanding bullets are a technologically advanced, match accurate, ALL-RANGE hunting bullet featuring highest-in-class ballistic coefficients and consistent, controlled expansion at ALL practical hunting distances. You can find them right here at Midsouth!
The name says it all! The 6.5 Precision Rifle Cartridge was designed to achieve the highest levels of accuracy, flat trajectory and extended range performance in a sensibly designed compact package.
The name says it all! The 6.5 Precision Rifle Cartridge was designed to achieve the highest levels of accuracy, flat trajectory and extended range performance in a sensibly designed compact package.
Utilizing moderate powder charges that result in repeatable accuracy, low recoil and reasonable barrel life, the 6.5 PRC produces high velocities for target shooting with performance well beyond 1000 yards.
Rifle makers currently chambering the 6.5 PRC include GA Precision, Gunwerks, PROOF Research, Stuteville Precision and Seekins Precision. Check back often as additional gun manufacturers confirm chambering the 6.5 PRC.
There’s a lot more to cover, and information is still coming in daily on the new products announced for next year. Stay tuned for a more in depth look at these items as we get a chance to demo them.
Determining and setting the correct case neck diameter is a critical, crucial step in the handloading process: Here’s all you need to know!
Here’s another I get (too many) questions about, and when I say “too many” that’s not at all a complaint, just a concern… This next hopefully will eliminate any and all confusions about this important step, and decision, in the reloading process.
Basics: A cartridge case neck expands in firing to release the bullet. If the load delivers adequate pressure, it can expand to the full diameter allowed by that portion of the rifle chamber. That diameter depends on the reamer used. After expansion and contraction, the case neck will, no doubt, be a bigger diameter than what it was before being fired.
Back to it: To get a handle on this important dimension, the first step is tools. As always. A caliper that reads to 0.001 inches will suffice.
You need to find three outside diameter numbers: fired case neck diameter, sized case neck diameter, loaded case neck diameter. If you know the loaded case neck diameter then it’s likewise easy to find out the case wall thickness, or at least an average on it if the necks aren’t perfectly uniform (and they won’t likely be unless they’ve been full-on outside case neck turned).
A fired case neck has to be sized back down to a dimension that will retain a bullet from unwanted movement (slippage) in the reloaded round. Case neck “tension” isn’t really an accurate term, in my mind, so I prefer to talk about “constriction.” The reason is that making a case neck diameter smaller and smaller does not, after a point, add any additional grip to the bullet. Once it’s gotten beyond maybe 0.005 inches, it’s just increasing the resistance to bullet seating not increasing the amount of tension or retention of the case neck against the bullet. The bullet is resizing the case neck, and probably getting its jacket damaged in the process. If more grip is needed, that’s where crimping comes in…and that’s (literally) another story.
IMPORTANT Always, always, account for the “spring-back.” That is in the nature of the alloy used to make cases. If brass is sized to a smaller diameter it will spring back plus 0.001 inches bigger than the tool used; if it’s expanded to a bigger diameter, it will spring back (contract) to 0.001 inches smaller than the tool used. This is always true! The exception is that as brass hardens with age, it can spring back a little more.
How much constriction should there be? For a semi-auto, 0.003 is adequate; I recommend 0.004. For a bolt-action, I use and recommend 0.002, and 0.001 usually is adequate unless the rifle is a hard-kicker. See, the main (main) influence of more resistance in bullet seating is to, as mentioned, set up enough gripping tension to prevent unwanted bullet movement. Unwanted movement can come from two main sources: contact and inertia. Contact is if and when the bullet tip meets any resistance in feeding, and gets pushed back. Intertia comes from the operation and cycling of the firearm. If there’s enough force generated via recoil, the bullets in rounds remaining in a magazine can move from flowing forces. However! That also works literally in the other way: in a semi-auto the inertial force transmitted through a round being chambered can set the bullet out: the case stops but the bullet keeps moving. I’ve seen (measured) that happen with AR15s and (even more) AR-10/SR-25s especially when loading the first round in. Put in a loaded magazine, trip the bolt stop, and, wham, all that mass moves forward and slams to a stop. Retract the bolt and out comes a case with no bullet… Or, more usually, out comes a case with the bullet seated out farther (longer overall length). Never, ever, set a constriction level on the lighter side for either of these guns.
Most seem to hold a belief that the lower the case neck constriction the better the accuracy. Can’t prove that by me or mine. If there’s too much constriction, as mentioned, the bullet jacket can be damaged and possibly the bullet slightly resized (depending on its material constitution) and those could cause accuracy hiccups. If it’s a semi-auto and constriction is inadequate, the likewise aforementioned bullet movement forward, which is very unlikely to be consistent, can create accuracy issues, no doubt. My own load tests have shown me that velocities get more consistent at 0.003-0.004 as compared to 0.001-0.002.
Benchrest competitors use virtually zero constriction, but as with each and every thing “they” do, it works only because it’s only possible via the extremely precise machining work done both in rifle chambering and case preparation. It is not, decidedly not, something anyone else can or should attempt even in an off-the-shelf single-shot. As always: I focus here, and in my books, on “the rest of us” when it comes to reloading tool setup and tactics. Folks who have normal rifles and use them in normal ways. And folks who don’t want to have problems.
So, find out what you have right now by determining the three influential diameters talked about at the start of this article. Most factory standard full-length sizing die sets will produce between 0.002 and 0.003 constriction. Getting more is easy: chuck up the expander/decapper stem in an electric drill (I use oiled emery cloth wrapped around a stone), and carefully reduce the expander body diameter by the needed amount, or contact the manufacturer to see about getting an undersized part. I’ve done that.
If you want less constriction than you’re currently getting, about the only way to do that one is hit up a local machinist and get the neck area in the die opened by the desired amount (considering always the 0.001 spring-back). Or get a bushing-style die…
The bushing-style design has removable bushings available in specific diameters. Pick the one you want to suit the brass you use. If you run an inside case neck expanding appliance along with a bushing die, usually a sizing-die-mounted “expander ball” or sizing button, make sure you’re getting at least 0.002 expansion from that device. Example: the (outside) sized case neck diameter should be sufficiently reduced to provide an inside sized case neck diameter at least 0.002 smaller than the diameter of the inside sizing appliance. That’s done as a matter of consistency and correctness that will account for small differences in case neck wall thicknesses. And when you change brass lots and certainly brands, measure again and do the math again! Thicker or thinner case neck walls make a big difference in the size bushing needed.
A Canadian Special Forces [sic] sniper looks to have taken out an ISIS fighter from a world-record distance of 11,316 feet, or about 2.2 miles away.
Now, as shooters and reloaders, we know there are a myriad of details which went into making a shot like this successful. “The spotter would have had to successfully calculate five factors: distance, wind, atmospheric conditions and the speed of the earth’s rotation at their latitude,” Says Ryan Cleckner, a former U.S. Army Ranger who served several tours in Afghanistan, and wrote the “Long Range Shooting Handbook.”
Atmospheric conditions also would have posed a huge challenge for the spotter.
Cleckner says, “To get the atmospheric conditions just right, the spotter would have had to understand the temperature, humidity and barometric pressure of the air the round had to travel through.”
BUT WHAT ABOUT THE HARDWARE???
“While the ammunition that Canadian special forces use in the TAC-50 is “off-the-charts powerful,” with some 13,000 foot-pounds of force when it comes out of the muzzle, the speed of a bullet, a 750-grain Hornady round, is not as important as the aerodynamic efficiency of the bullet.”
Yes. You read it correctly. The rifle is great, the spotter was spot-on, the shooter held to his technique.
One of the largest factors was the bullet. A HORNADY bullet.
“The key to having a sniper round travel that far and hit a small target has less to do with speed and more to do with the efficiency with which the projectile moves through the air,” he said.
“That’s because while sniper bullets exit the muzzle at several times the speed of sound they eventually slow down to less than the speed of sound, and at that point they become less stable. An efficiently designed bullet reduces that instability, he explained,” Says Michael Obel of Fox News.
“When it all comes together, it’s ‘mission accomplished’.”
Well done, soldier! We appreciate you essentially disrupting a deadly operation about to take place in Iraq by these barbarians.
Understanding the relationship between bullets and barrel twist helps prevent mistakes. Here’s what you need to know…
Why am I devoting this space this time to such a topic? Well, because it’s commonly asked about, and, no doubt, because it influences some of the decisions and options faced in choosing the best-performing load for our needs. Making a mistake in choosing twist can limit both the selection and performance in the range of usable bullet weights and styles.
First, barrel twist rate is a component in the architecture of the barrel lands and grooves. The lands and grooves form a spiral, a twist, that imparts spin to a bullet, and the rate of twist is expressed in terms of how far in inches a bullet travels to make one full rotation. “1-10” (one-in-ten) for example means “one full rotation for each ten inches of travel.”
Bullet length, not weight, determines how much rotation is necessary for stability. Twist rate suggestions, though, are most usually given with respect to bullet weight, but that’s more of a generality for convenience’s sake, I think. The reason is that with the introduction of higher-ballistic-coefficient bullet designs, which are longer than conventional forms, it is easily possible to have two same-weight bullets that won’t both stabilize from the same twist rate.
The M-16/AR15 barrel changes give a good example. Short history of mil-spec twist rates: Originally it was a 1-12, which was pretty standard for .224-caliber varminting-type rounds, like .222 Remington, which were near-universally running bullet weights either 52- or 55-grain. That worked with the 55-grain FMJ ammo issued then. Later came the SS109 63-grain round, with a bullet that was a bit much for a 1-12. The military solution was total overkill: 1-7. That’s a very fast twist.
Commercially, the 1-9 twist became the standard for .223 Remington for years. It’s still popular, but is being replaced, as far as I can tell, by the 1-8. An increasingly wider selection of barrels are done up in this twist rate. I approve.
I’d always rather have a twist too fast than not fast enough. For a .223 Rem. 1-9 is not fast enough for anything longer than a routine 68-70-grain “magazine bullet,” like a Sierra 69gr MatchKing. 1-8 will stabilize any of the newer heavier bullets intended for magazine-box cartridge overall lengths, like a Sierra 77gr MatchKing. An 8 twist will also shoot most of the longer, higher-BC profiles, like the Sierra 80gr MatchKing (which is not intended to be assembled into a round that’s loaded down into a magazine).
Other popular calibers have likewise edged toward faster and faster “standard” twist rates, and that includes 6mm and .308. Once those were commonly found as 1-10 and 1-12, respectively, but now there’s more 1-7s and 1-9s offered. Reason is predictable: longer and heavier bullets, and mostly longer, have likewise become more commonly used in chamberings like .308 Winchester and 6XC.
The tell-tale for an unstable (wobbling or tumbling) bullet is an oblong hole in the target paper, a “keyhole,” and that means the bullet contacted the target at some attitude other than nose-first.
Base your next barrel twist rate decision on the longest, heaviest bullets you choose to use, and at the same time realize that the rate chosen has limited those choices. If the longest, heaviest bullet you’ll shoot (ever) is a 55-grain .224, then there’s honestly no reason not to use a 1-12. Likewise true for .308-caliber: unless you’re going over 200-grain bullet weight, a 1-10 will perform perfectly well. A rate that is a good deal too fast to suit a particular bullet may cause damage to that bullet (core/jacket integrity issues), and I have seen that happen with very light .224 bullets, like 45-grain, fired through, say, a 1-7 twist. At the least, with that great a mismatch you might not get the velocity up where it could be.
Bullet speed and barrel length have an influence on bullet stability, and a higher muzzle velocity through a longer tube will bring on more effect from the twist, but it’s a little too edgy if a particular bullet stabilizes only when running maximum velocity. My failed 90-grain .224 experiment is a good example of that: I could get them asleep in a 1-7 twist 25-inch barrel, which was chambered in .22 PPC, but could not get them stablized in a 20-inch 1-7 .223 Rem. The answer always is to get a twist that’s correct.
Effects on the load itself? Yes, a little at least. There is a tad amount more pressure from a faster-twist barrel using the same load, and the reason is initial bullet acceleration is slower.