I'll have to disagree with the idea IMR 4064 is too slow for the Garand. It's actually cited by many as being the preferred match powder over IMR 4895 in the Garand. WC852, a spherical propellant (sold in canister grade by Hodgdon as H380) was, like 4895, developed for .30-06 military ammunition. It was used in LC M2 ball, yet it is slower than 4895, 4064 or even 4320 on Hodgdon's own burn rate chart. So burn rate is not really a problem with 4064 in the Garand at all. It is actually so close to that of 4895 that the difference is of no adverse consequence to the Garand, but, the difference isn't quite simple, either:
John Feamster did an interesting experiment with 4064 and 4895 firing the 168 grain Sierra MatchKing in the M14 that was published in the Precision Shooting Reloading Guide. He loaded the two powders to fixed velocities. Both are single-base and have about the same energy content per unit weight. At 2200 fps it took less 4064 than 4895, indicating 4064 was the faster powder. By the time he got to 2400 fps the charge weights were equal, indicating they had the same burn rate at that pressure level. At 2500 fps it took more 4064 than 4895, indicating it was now acting as the slower of the two.
That difference in relative burn rate under different conditions is caused by mainly by the different grain geometries. It reminds us that burn rates on a chart are only true under one fixed set of test conditions, and are not correct rankings under all conditions. The experiment also showed that the slope of the rate of change in burn rate with pressure is faster for 4895 than for 4064. That means 4064 is more tolerant of charge weight error and less sensitive to other factors that affect pressure, like temperature and case capacity variation. Those reasons make it more forgiving and easier to use as a match powder.
Another factor is that 4064 has lower bulk density than 4895. As a result, it fills the .30-06 case better, reducing velocity variations. That helps it serve well at longer range in Garand match loads.
For 4064 Garand match loads, John Clark published a number of them in 1985 in Handloader #114, and in the Rifleman in 1986 (I've forgotten the specific issue, though).
