Harley,
When loading for the M1A, you have to take some of the loading data with a grain of salt. Some of the "accuracy" loads they list are high speed rds for bolt guns, which just won't fly with a gas operated gun.
Based on my experimentation with 4064 with 150gr FMJs, I would have to say that a load between 43 & 44gr for your 168 J4s should be in the ballpark. Of course, this also depends on what cases you are using. Military cases, like Lake City, are thicker-walled and take less powder than standard Winchester, Remington, etc cases. The 43 to 44gr would be for military cases - for commercial cases, I would start around 43.5 and work up as far as 45gr. And this is using the military match standard 2.830 OAL.
When loading for the M1A, you have to take some of the loading data with a grain of salt. Some of the "accuracy" loads they list are high speed rds for bolt guns, which just won't fly with a gas operated gun.
Based on my experimentation with 4064 with 150gr FMJs, I would have to say that a load between 43 & 44gr for your 168 J4s should be in the ballpark. Of course, this also depends on what cases you are using. Military cases, like Lake City, are thicker-walled and take less powder than standard Winchester, Remington, etc cases. The 43 to 44gr would be for military cases - for commercial cases, I would start around 43.5 and work up as far as 45gr. And this is using the military match standard 2.830 OAL.
