The Garand was type classified in 1936. It used a service round developed in 1906. Technology was not as sophisticated as today, plain carbon steel was the primary material used in firearms. The 1906 round used powders that were obsolete in the 1930’s , operating velocities and pressures were lower. The velocity of the original 1906 round was just at 2700 fps. As I will address later, it was 2700 fps in a Frankfort Arsenal pressure barrel. Pressures were also low, nothing greater than 50K psia. Based on American Rifleman match ammunition data, there was a lot of ammunition which peak pressures were closer to 40 Kpsia than 50K psia. Might have even been loads that were high 30 Kpsia. What mattered was velocity, port pressure. The breech pressure was a not to exceed. Today’s’ commercial ammunition zips a 150 grain bullet at 2900 fps and I believe pressures are 60 Kpsia.
Even though the Garand was made of alloy materials it still used the M1906 cartridge and was designed to operate within the pressures and velocities of the 1906 cartridge. There are several first order considerations when developing loads for the Garand. The first is port pressure. This rifle is limited by port pressure. If port pressure is too high than the mechanism is over accelerated which will bend operating rods and cause malfunctions.
When the 2001 Federal loaded ammunition was used at the Camp Perry Garand Match, it was loaded to commercial specifications. The retired Marine I was scoring, he old enough to be a Korea War vet, his like new Garand malfunctioned with this Federal ammunition. I can recall seeing his partially loaded clip jump up out of the receiver in rapid fire prone, causing a jam, and the Marine looking angrily at it. He pulled the clip out and tossed it on his mat. Since the Garand Match is a no alibi match, the Marine decided to quit for the day and shoot the ammunition at home. There were so many reports of ammunition created malfunctions that the next order of Federal ammunition was significantly reduced in velocity and pressure.
I believe it was that year during the standing stage that we all heard a rifle discharge after the "load" command. My hutmate was a near the shooter and it was a inbattery slamfire. Federal ammunition has very sensitive primers and when that primer went off, everyone heard it.
There is another consideration, not talked about, and that is fatigue to the receiver sidewalls. The bolt rebounds off the back of the receiver in both Garands and M1a’s. The sidewalls absorb that impact and given enough impacts receivers have been known to crack. The attached pictures are of one example. Hot loads that smack that receiver heel even more are not needed or wanted.
As for powders. IMR 4895 has got to be the “nominal” powder for Garands and M1a’s. This powder loaded most of the WWII and match ammunition for these rifles. The pressure curve is correct for these rifles. There are close copies or just duplicates of IMR 4895 that are excellent powders and if the price is right, are worthy of consideration.
Accurate Arms told me that AA2495 copied the pressure curve of IMR 4895, grain for grain I can’t tell a difference. Instead of naming their power AA4895 they named it something different and confuse everyone. H4895 is a little different but that may be due to the differences in lots. When H4895 first came out it was supposed to be a copy of IMR 4895. These are excellent stick powder choices for the Garand/M1a.
Accurate Arms told me that AA2520 duplicates the IMR 4895 pressure curve, grain for grain. If you want to use a ball powder, AA2520 is a good choice. I prefer the stick powders but AA2520 shots well.
When developing loads I used ball ammunition from the period when the Garand was the service rifle. I believe late 60’s 30-06 ammunition was tailored towards the 30-06 machine guns left in inventory.
My TW56 ammunition gave me 2680 fps out of a 26” match barrel. That gave me an upper velocity boundary when comparing a load of 47.5 grains IMR 4895.
People quote data from Technical manuals not understanding that all velocities and pressures were traceable to Arsenal pressure barrels. Government lot acceptance was conducted with pressure cartridges developed in a Frankfort Arsenal barrel (I assume FA) and vendor pressure barrels were corrected to the FA values. The only barrel which gave the TM velocities and pressures were one FA test barrel. That is why I shoot military surplus in my barrels and compare performance from my data, not TM data. And my data is slower than the TM specs.
As you can see from the data below, when fired in service grade Garands, that load of 47.5 grains of IMR 4895 is just over 2600 fps in a 24” service barrel.
As for maximum loads, I consider a 150 grain bullet with 47.5 grains IMR 4895 a maximum load for my Garands. It would not hurt to cut this load by a grain.
I regularly shoot a 168 Match with 47.0 grains IMR 4895.
My load of 175 Match with 47.0 grains IMR 4895 is probably a little hot for this action, but the velocities are under the 2650 fps for 174 FMJ match ammunition, so it is probably OK.
M98 30-06 26" 1-10 Wilson Barrel
150 gr FMJBT TW 56 Ball
24 Mar 04 T= 70 °
Ave Vel = 2680
Std Dev = 31
ES = 78
Low = 2620
High = 2698
N = 6
150 gr Sierra Match HPBT 47.5 IMR 4895 CCI#34 190 ≤ WWII ≤ 195 OAL 3.290"
24 Mar 04 T= 70 ° F
Ave Vel = 2722
Std Dev = 26
ES = 76
Low = 2673
High = 2749
N = 10
M1 Garand 5 827 YYY GI Barrel
150 gr Sierra Match HPBT 47.5 IMR 4895 CCI#34 190 ≤ WWII ≤ 195
24 Mar 04 T= 70 ° F
Ave Vel = 2619
Std Dev = 28
ES = 101
Low = 2559
High = 2660
N = 16
M1 Garand 5 925 YYY GI barrel
150 gr Sierra Match HPBT 47.5 IMR 4895 CCI#34 190 ≤ WWII ≤ 195 OAL 3.290"
24 Mar 04 T= 70 ° F
Ave Vel = 2630
Std Dev = 33
ES = 109
Low = 2580
High = 2689
N = 16
M1 Garand Match Douglas Barrel 1:10 twist
168 Sierra Match 47.0 grs AA2495 wtd WLR FC Cases OAL 3.30"
5 May 00 T = 82 ° F
Ave Vel = 2632
Std Dev = 16
ES = 50
Low = 2616
High = 2666
N = 10
168 gr Sierra Match 47.0 AA2520 WWII cases (185 to 190 gr) WLR OAL 3.30"
5 May 00 T = 82 ° F )
Ave Vel = 2658
Std Dev = 35
ES = 85
Low = 2612
High = 2697
N = 5
175 Sierra Match 47.0 grs AA2495 wtd CCI 34 R-P Cases OAL 3.30"
5 May 00 T = 82 ° F
Ave Vel = 2631
Std Dev = 8
ES = 23
Low = 2617
High = 2640
N = 5