January 04, 2011
One-Size-Fits-All Powder, Rotational Projectile Breakdown, Heavier Than Normal Bullets...
Q. I like to collect and shoot old military-surplus guns, and I was hoping the reloading experts could offer some useful advice to ease my efforts in keeping the old warhorses fed. Since many of the old military calibers haven't been commercially loaded in decades, reloading will be pretty much a necessity. Even for those calibers that are still commercially available, I'll get a lot more shooting for my money by reloading.
Is there a powder that might perform adequately for all/most military smokeless loads? I don't care about single-hole accuracy (won't get it using issue iron sights anyway), warp-speed velocity, or zapping elk from three zip codes away. I realize that a general-purpose, across-the-board powder will be outperformed by specific powders in individual caliber loadings. My desire is to greatly simplify purchasing and cut down on reloading headaches by using a single powder--and to be able to use that powder to come close enough to the original military loads' ballistics that I can use the rifles' iron sights without having to aim too much over or under the target. I have a large rifle collection, with several each in the 6.5mm, .30, and 8mm calibers found in mostly World War I and World War II rifles.
Likewise, is there a powder you could recommend that might do a reasonable job in most handgun loads?
Chris AlexanderKingwood, TX
A. There's not one "universally" optimum propellant for either rifles or handguns; however, I'll bet IMR or Hodgdon 4895 would come close for .223, .308, .30-06, 6.5, 7mm, and 8mm Mausers. 4895 is not suitable for .30 Carbine, but it is probably okay in 7.62x39. Check Hodgdon's website and Reloading Data Center for specific information to find suitable load recipes for all of these.
As for a one-size-fits-all handgun powder, again there's not just one universal propellant that's best for all. However, Alliant Unique, Accurate Arms No. 5, and Hodgdon Universal Clays are some that probably come the closest to filling that bill. Again, you should always consult reputable data sources for specific load data for any cartridge.
Lane PearceReloading Editor
Rotational Projectile Breakdown?
Q. I really enjoyed the column by Allan Jones that referenced rifling twist rates. I have always assumed the engineers at the rifle manufacturer have a reason for the twist rate they make standard. I figured that rate was based on the ammo on the market at the time. I will admit it's "minute of deer" accuracy I am worried about, so I passed over the "higher" twist with barely a thought when buying an AR with a 1:7 twist barrel.
I was surprised to read about the "truths" of overstabilization, and I have to say that the specific example given regarding the AR .223 doesn't agree with my experience. While I am not an engineer, and haven't chronographed the different loads or photographed them in super slow-mo, I can see what prints on the paper.
And that has me perplexed! I am not questioning what Jones stated, but I am wondering if he can offer any idea why my experience would be so different?
Awhile back I purchased a megapack of Remington 45-grain HP .223 on sale for "plinking" at the range, then heard about truth #1 ("rotational projectile breakdown") from some article. "Great," I thought, "I have a boatload of flyers to shoot!" But that was not the case. That ammo shoots great!
My 1:7 twist 20-inch HBAR AR clone prints its best groups with the Remington 45-grain HPs, and groups with Remington 55-grain green-and-white-box FMJ are about 10 percent larger. Could it be these are "tougher" than other bullets? Are they not the type of bullet Jones was talking about? Perhaps I am missing something here. Both will group about 1 MOA if I do my part, so I might be splitting hairs, but there was definitely no self-destruction of bullets from over-rotation. No indication of wobble in the Shoot-N-C targets either.
I had written off truth #1 as "myth." Should that "truth" be tested again with modern ammo? I can't find anyone who has ever actually witnessed "rotational projectile breakdown" firsthand, at least from an AR platform .223. Perhaps it applies more to lighter projectiles in smaller calibers? Anyway, it was a great article. Keep up the good work!
Steven HaynieDeerfield Beach, FL
A. The come-apart in flight due to a too-fast twist is a "feature" of many thin-jacketed varmint bullets. We saw it on our own ranges at Speer when the fast-twist .223 Rem./5.56mm barrels appeared. I also talked to my friends at Sierra; they saw the same thing in their labs and heard it from their customers. We first got customer calls complaining of break-ups when Ruger changed the twist in its Mini-14s to 1:7. The Ruger shooters were often using the Speer 55-grain SP with cannelure as recommended by the riflemaker at the time, and the bullets seemed to be splitting at the inherent and unavoidable line of shear resulting from the forming of the cannelure. Our thin-jacketed 52-grain HP and the even thinner 50-grain TNT created shotgun patterns from the Rugers unless downloaded to around 2,800 fps. Sierra independently came up with a similar velocity limit for its varmint bullets of that period.
What you are likely seeing in getting good results is an effort by manufacturers to beef up their jackets in response to the fast-twist guns. Speer reacted a few years back with a 55-grain TNT that had a tougher jacket than the original. If your Remington bullets are the Power-Lokt variant, the jacket is chemically bonded; that would go far in reducing in-flight separations (the technical term for a bullet failing to get to the target in one piece). An FMJ bullet usually has a heavy jacket to start with and is much less affected by twist rate. A solid-copper bullet is also immune as long as the tip and/or HP cavity is not eccentric.
A precision barrel that is very smooth also helps. Any barrel damages a bullet jacket to some extent; rough barrels can encourage break-up even with standard twists. The smaller the machining marks, the less this damage and the more rotational velocity the bullet can withstand. I suspect your rifle has a very fine barrel.
Allan JonesBallistics Editor
Heavier Than Normal Bullets?
Q. Would Layne Simpson please comment on the "trend" in large-caliber rifles toward using heavier than normal bullets? For example, 300 grains in the 9.3x62, 350 grains in the .375 H&H, and 550 grains in the .458s.
Robert M. Petersen, Lt. Col.,USAFR, Ret.CAE Pilot Si
mulator InstructorKeesler AFB, MS
A. I am unaware of the trend you speak of. If there is a trend today, I believe it is to use less bullet weight rather than more due to the availability of designs that are capable of upwards of 100-percent weight retention during expansion. Dropping back one level from the top in weight with a bullet of monolithic construction, such as the Barnes X-Bullet, is commonly done, but mainly because it is longer than a lead-core bullet of the same weight and when the two are seated to the same overall cartridge length, it occupies more of the powder space in the case. Reducing the weight of a bullet also reduces its length. This is a good plan when loading a cartridge such as the .458 Winchester Magnum with its comparatively small powder capacity, but for larger cases, such as the .458 Lott and .460 Weatherby Magnum, I continue to believe that the more traditional 500-grain bullet is the way to go regardless of construction.
For decades my rule of thumb for cartridges in the medium and large calibers has been to use a bullet with a sectional density in the neighborhood of .300 when deep penetration on the larger game is desired. Examples are 250 grains in .338 caliber, 285 grains in 9.3mm, and 300 grains in .375. In my opinion, those bullet weights are optimum in cartridges like .338 Winchester Magnum, 9.3x62mm, and .375 H&H Magnum. Heavier weights with even higher sectional densities are fine when used in the faster cartridges, but I really see no advantage in going beyond the standard weights with modern bullets.
Layne SimpsonExecutive Field Editor