This is for 30-06 LC Match, which is a 174 grain bullet
For GI ball, I interpolate.
I bought a case of TW56 ball at the 2001 Garand Match at Camp Perry. This was good stuff for ball ammo. It is my opinion that the best military 150 gr Garand chow is the 50’s ammo, made when Garands were the service rifle. Late 60’s vintage stuff, LC69 for example, that is not as consistent, is inaccurate, is hotter, and only machine guns were around to shoot the stuff. Garands were no longer a front line rifle for the US. I would expect the standards on the later ammunition to be relaxed as the ammunition makers had been converted to Contractor, no one gave a darn, and the chain of command was up to their pants pockets fixing M16 problems.
I did a comparison between TW56 and my loads. You can see that in a 26” match barrel I got 2680 fps. My “test” ammo was 150 Sierra match. That got 2722 out of a 26” match barrel. When I shot the 150 Sierra match in two rack grade Garands, I got 2630fps and 2619 fps. My interpolation is that the TW56 ball ammo would also drop 100 fps or so in a rack grade. But I have not tested that and probably will not unless I am bored.
I may when I finally decide to shoot some of my unopened ammunition boxes of 30-06 LC match.
For me, I would keep all 150 grain bullets less than 2700 fps in my Garands. 2650 fps is not bad if 2630 fps will function the mechanism and give reasonable accuracy.
It is a big mistake to look at the technical manuals and copy that number of 2750 fps plus or minus 50 fps. That velocity (and the associated pressures) were calibrated to a single Government pressure barrel (and I don’t remember where) at a Government Arsenal. The Government acceptor took calibration cartridges and fired them in the vendor pressure barrels. My data sheets for the acceptance of WC852 show that they “corrected” the reading in the vendor pressure barrel, which incidentally were quite a bit less than in the Government barrel.
Instead of trusting paper values I trust my over the chronograph velocities. If the chronograph values are a lot less than the published military spec values, I believe this is due to the differences in the measuring equipment at the Government Arsenal, vendor ammunition plant, and my chronograph. .
I could be all full of it, but going magnum is not good for these mechanisms.
M98 26” 1-10 Wilson Barrel
150 gr FMJBT TW 56 Ball
24 Mar 04 T= 70 ° F
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 5 925 XXX
150 gr Sierra Match HPBT 47.5 IMR 4895 CCI#34 190 ≤ WWII ≤ 195
24 Mar 04 T= 70 ° F
Ave Vel = 2630
Std Dev = 33
ES = 109
Low = 2580
High = 2689
N = 16
M1 Garand 5 827 XXX
150 gr Sierra Match HPBT 47.5 IMR 4895 CCI#34 190 ≤ WWII ≤ 195
24 Mar 04 T= 70 ° F OAL 3.290"
Ave Vel = 2619
Std Dev = 28
ES = 101
Low = 2559
High = 2660
N = 16