10-30-2007, 10:32 AM
Join Date: Jan 2006
COPPER JACKETS, STEEL JACKETS, ARMOR PIERCING & BOAT-TAILED BULLETS!
Posted By: Dick Culver <firstname.lastname@example.org>
Date: Tuesday, 20 August 2002, at 11:04 p.m.
I read with interest your posts below asking about destructive qualities of various .30-caliber U.S. Projectiles in our former service rifles. The problem was (or seemed to be) that everyone was talking at once and nobody was answering the original question (which wasn't too clear). Here we have several projectiles in question:
1) The original cupro-nickel jacketed bullets used almost universally until 1922 (and somewhat beyond to use up available supplies on hand).
2) The use of tin to beat the cupro-niclel fouling problem. Remington called their solution "Lubaloy" which was essentially identical to modern day "gilding metal" still in use today.
3) The M2 AP (armor piercing round) with a tungsten core surrounded by lead and jacketed with gilding metal.
4) The WWII field expedient solution to the copper shortage which was a copper-plated mild steel jacket permitted as a limited standard during the war. Unfortunately, following the war, the mild steel jacket was used again from time to time when the price of copper was up - actual jacket material on M2 Ball from the late 40s on is sometimes one thing, and sometimes another. The only sure way to detect it is to use a magnet on the jacket.
Hatcher's Notebook (as pointed out below) has much of the early information contained therein, as well as many of the writings of small arms pundits of the day.
1) M2 Ball using gilding metal jackets was the most accurate (non-match) ammunition and easiest on the bore.
2) NEVER, EVER shoot AP Ammunition in your good rifle bore.
3) M1 Match Ammo (172/3-grain boat-tailed bullet) was very accurate but wore your bore out much faster than the flatbased variety due to the gas getting forward of the bullet base and causing "gas-cutting" in the bore.
4) Copper plated mild steel jacketed ammo was considered OK according to Phil Sharpe, a noted Army Ordnance Officer and a long time contributor to the American Rifleman's "Dope Bag" (Phil was one of the gents responsible for the development of the .357 Magnum in the 1930s).
WHAT ARE THE TRUTHS?
Turns out that 1, 2 and 3 are patently false, and in my opinion, the jury is still out on number 4. Phil Sharpe was one of the "I'd never shoot AP in MY good rifle boys" but it turns out that he should have known better, according to a paper published by Frankfort Arsenal in the mid 1940s... I'll publish my personal snyposis below (written for one of our posters asking the same question several years ago).
At the extreme bottom of the post is the URL for an article I wrote for the CMP a year or two ago concerning the use of tin to eliminate cupro-nickel fouling in the M1903 Rifle bores in 1921... My references are from Hatcher's Notebook, old manuscripts and my Dad's stories (he fired in the Nationals for the Marines in 1921 and was there for the issue of the so-called "Tin Can Ammo." Format is in PDF - if somebody can't bring up PDF, e-mail me and I'll send you the article as an attachment.
FRANKFORD ARSENAL TEST OF .30-'06 CALIBER BARREL LIFE USING ISSUE U.S. ARMY BALL AND AP AMMUNITION
Answer to a question asked on the CSP Board several years ago:
The short answer (as you have apparently just found out from personal experience) is that your barrel should be good for another 5000 rds (at least according to a Frankfort Arsenal Report conducted in the 1945/1946 timeframe.
Old wives tails had long held that a maximum barrel life with service ammunition was approximately 5000 rds or less. Some said as few as 3500. And just EVERYONE knew that using AP would trash your barrel in a heartbeat. On the flip side of the coin, most experts considered that M1 (172-gr) Ball, (essentially a precursor of the 172-grain FA Match 30-'06) to be extremely accurate, however according to urban legend, it was BOUND to "eat" barrels at an accelerated rate due to the 9 degree boat-tail that would allow hot gasses forward of the bullet base while the projectile was still in the bore!
As it turns out, virtually every old wives tale was pure unadulterated "Moose Manure", however some very high priced help published them as gospel. Clark Campbell in his excellent book "The '03 Springfield" parroted the widely held belief concerning the 172-grain match ammo being hard on the bore, and Phil Sharpe, one of the developers of the .357 Magnum Cartridge an a WWII Army Ordnance Officer and regular contributor to the "Dope Bag" in the American Rifleman) put out the information in his "Complete Guide to Handloading" that while the mild steel jackets of the WWII .30-'06 Ball wouldn't harm the bore of your favorite target rifle, he would not shoot .30 caliber M2 AP in his rifle under ANY circumstances... Just goes to show you how wrong you can be.
Frankford Arsenal grew weary of the stories and decided to conduct a test to determine if they were correct. Without going into great detail, they found that when using either M1 Ball (almost identical to the later M72 Match Ball) or M2 Armor Piercing, the accuracy actually improved up through the first 1000 rounds or so (don't hold my feet to the fire on the exact numbers as I don't have my references in front of me and am too lazy to dig 'em out right this second). They continued to fire the test (using a test rack) and it seemed that the accuracy "improvement" seemed to taper off after 1000 rounds, but the accuracy itself did NOT decrease. The accuracy continued to be excellent to outstanding through at least 8000 rounds. They finally ceased the test, not because the accuracy was declining, but because they simply got tired of firing, since the accuracy showed no sign of decreasing. FA estimated that the excellent accuracy should continue through at least 10,000 rounds and probably beyond.
This was NOT the case with the 150 grain M2 Ball however, it seems that the accuracy began to drop off after about 3500 - 4000 rounds (again don't hold my feet to the fire, I plan to write an article on this and will include the actual figures when I do). The only common thread to the barrel longevity I can personally see, is that both the M1 Ball (172 gr. Match) and the 165-168 gr. AP have a boat-tailed configuration (9 degree for the 172 and a much less obvious 6 degree for the AP).
Throat erosion is another bugaboo that is usually blown out of proportion. We had a gent by the name of Eric England shooting for the Marine Corps for years. He had a favorite M70 that the Ordnance folks kept trying to get him to turn in since the throat was essentially non-existent... Eric steadfastly refused because he kept setting National Records with a shot-out throat... An old rule of thumb used to be that two things happened if your bore was shaped like a pyramid (i.e., bigger at one end than the other). If it was big at the muzzle and small in the throat, you had a boat anchor. If it was big at the throat and small at the muzzle, you had a (potential) shooter - please understand that I'm talking "relative measurements" here... In other words, if your muzzle was tight you were usually OK, but not the other way around.
At any rate, I've raved on much further than I had planned, but I think you can plan on an extremely long accuracy life out of your M1 or M1A barrel if you continue to use 168 -175 gr. boat-tailed bullets at normal velocities…