WW2 ammo pressure test results

[Mike Venturino]

Larry Gibson asked for this information but I thought perhaps more of you might like to see it also.

This data was gathered in the Hornady lab and is psi - pounds square inch - except for the 7.62x54mm Russian ammo. It was tested in the Hodgdon lab and is cup - copper units of pressure.

.303 British - Mk VII 175 grain FMJ dated 1943 - 2498 fps - 50,100 psi

.30-06 - LC-44 162 gr. AP bullets - 2800 fps - 61,600 fps.
.30-06 - LC-53 (Korean War) - 150 gr. FMJ - 2740 fps - 50,300 psi

8x57mm - 197 gr. FMJ - 1945 - 2494 fps - 50,000 psi

7.62x54mm R Russian - 1945 - 147 FMJ - 2832 fps - 41,400 cup

If I get a chance for either company to test that 1935 8mm stuff I picked up last weekend, I'll post the results.

Mike V.

[KCSO]

Very interesting and my thanks. I am amazed b the pressure of the 303 ammo! This is suppose to be a low pressure round. Most books say under 45,000 and here the factory ammo is the same as a 30-06. 2498 for a 175 bullet is moving right along too.

[3006guns]

I heard an interesting rumor not too long ago......that much of the cordite fueled .303 was burning at higher pressures than originally loaded. This was supposedly due to the cordite breaking into small pieces from years of handling. Anyone else heard this?

[felix]

High pressure, no. Heat, yes. ... felix

[Larry Gibson]

Thanks Mike.

Those psi figures are very close to what I've gotten with the M43 Oehler in my test rifles. Sometimes higher and sometimes lower but that's expected with lot to lot variation and different test rifles used.

Larry Gibson

[atr]

yea,,,that pressure reading from the .303 British caught my eye also....
very interesting

[KCSO]

I've pulled apart a lot of cordite ammo some as recently as a year ago and I NEVER saw any cordite breaking up. It was put in the case and the case formed around it so I doubt it could even move. When you break it down with a hammer puller the bullet comes out and you have to pound more to get the cordite to come out and you get a long stick.

[Char-Gar]

Always bear in mind that WWII ammo was produced in huge qualities and quality control was not always the best. Also, this stuff is 65 years old, and unless stored under controlled conditions, may have suffered some change in ballistic performance.

[Multigunner]

I heard an interesting rumor not too long ago......that much of the cordite fueled .303 was burning at higher pressures than originally loaded. This was supposedly due to the cordite breaking into small pieces from years of handling. Anyone else heard this?

Cordite MD was more prone to breakage of the strands than Cordite Mk1 but it would take serious vibration to cause strands to breaka once loaded as a bundle into the casing.
Cordite is subject to sweating nitroglycerine if exposed to temperatures over 125 degrees for any length of time, the nitro collecting in the bottom of the case. Exposure to freezing temperatures for several days can result in crystalized nitro pushing out of the strands, but once temperature returns to normal that nitro is reabsorbed.

CUP pressure of WW1 era MkVII was recorded by U S Ordnance as 45,400 CUP. Unlike todays SAAMI pressure quotes they didn't round off to the nearest one thousand.

MkVIIz (the z being a sideways N to denote Nitrocellulose rather than cordite) could be subject to greater variations in pressures due to less sophisticated manufacturing techniques. This ammo was most often reserved for machinegun indirect fire, like the MkVIIIz. MG gunners sometimes reported excessive pressures with the MkVIIIz in hot desert environments.

The most common cause of excessive pressures from old milsurp ammo, other than degraded propellents, is hardening of sealants and water proofing compounds applied to the case neck. Cold soldering of bullet to case neck is another less common cause.
I've read that when much fresher surplus 7.62 NATO ammo gave poor groupings and pressure signs U S Army marksmen took to using an inertial puller to start the bullet from the neck then reseated it again, breaking the hold of age hardened sealant. The ammo then grouped very nicely with no pressure signs.

.303 ammo that exceeds the SAAMI maximum average working pressure of 45,000CUP / 49,000 PSI should not be used.
Surplus ammo has been declared surplus for several reasons, failure to meet pressure specifications is probably the most serious.

[Dobetown]

Thanks Mr. Mike
Good info, I used to shoot a of 40's repack in M1's and 03's. When I could see chamber reamer marks on the brass I figured it was pretty warm.
Theres a guy at Wheel guns could use some help BP 45 colt loads.

[JeffinNZ]

Multigunner hit the nail on the head with the .303 Brit. CUP not PSI.

[3006guns]

Thanks for the info. Like I said, it was a rumor and not being completely familiar with cordite I had to ask. The few cordite rounds I've pulled apart always had intact propellant.

[sqlbullet]

Thanks Mike, very good info!

For any new Garand shooters/reloaders, please keep in mind that peak pressure and port pressure are different. A load that makes these pressures and velocities at the chamber may or may not be safe for the Garand action.

I think in general the Op-rod is tougher than we give it credit for...but, they aren't making any more, so protect yours!

[ironhead7544]

I remember hearing that the AP 30-06 was loaded to higher pressures for the aircraft MGs. It was not meant for the M1 rifle. Dont know how true this is but it is higher that the ball.

[405]

Mike,
Thanks for posting this info!

One clarification though, I assume (pretty sure) this is a typo. ".30-06 - LC-44 162 gr. AP bullets - 2800 fps - 61,600 fps."

No matter, that 61,600 (psi) is a stiff one!

[madsenshooter]

Another thing to bear in mind is that dry powder burns different than fresh. I pulled down a 50 cal round my grandma had in her knicknack cabinet since my uncle, a B24 belly turret gunner brought it home from from gunnery school. Powder was dry as a bone. Where did the moisture go? I'd say into the green stuff that was on the inside of the case. It was a tubular powder, some of it had crumbled to dust.

[MakeMineA10mm]

Mike,
Thanks for posting this info!

One clarification though, I assume (pretty sure) this is a typo. ".30-06 - LC-44 162 gr. AP bullets - 2800 fps - 61,600 fps."

No matter, that 61,600 (psi) is a stiff one!

No, I think that is perfectly accurate. I've been doing a heck of a lot of research about WWII 30-06 US military loads, and all the sources I've found that include load data, velocity data, and/or pressure data, consistently point out that the 162gr AP rounds ran at 2800+ FPS and were loaded with the same powder charge as the 10gr lighter M-2 Ball bullets. I only found one source that listed pressure, and it said 55,000 psi. (Remember that back in WWII they used CUP, but called it PSI.) I'm pretty sure that 55,000 cup would be right around 62,000 psi, which reinforces my belief that M-2 AP ammo is very much not a good choice for shooting in our Garands! I had originally wanted to replicate that load (except with 165gr Nosler Partitions) for hunting with my Garand, but I've given up the idea.

I'm loading the Noslers, but I'm happy with 2650-2675fps, which is as hot as I think a bullet that weight can be pushed and stay within safe op-rod pressures. This load-level, by the way, is the same as M-1 Ball (174gr bullet) and M-72 Match (172gr bullet), both of which show lower pressures than the M-2 AP round.

I'm confident the US military looked at the AP round as more of a MachineGun round, or if it was used in the rifle, they figured that the Garand could handle it (because it was new and "built tough" - at least for back then), and if a few op-rods bent, the unit armorers or Ordnance personnel replaced them in field maintenance or Theater-Ordnance shops and re-issued the rifles...

[garandsrus]

The typo was fps vs psi....

John

[Mike Venturino]

Corrected!

[MakeMineA10mm]

The typo was fps vs psi....

John

OOPS!!! Sorry 405!!

Thanks Garands-R-Us!