4064 is a good powder with a burn rate right next to 4895, it is just tougher to meter.Hornady lists a maximum charge of 43.2 grains of IMR4064 in their 308 service rifle section for a 150 grain bullet at 2700 fps velocity. And that is with commercial cases and regular primers.
Using the search function, I've found where it has been posted several times here in the past of NRA data giving a charge range of 42-44 grains of IMR4064 using GI Lake City cases.
The NRA data would seem to be high to me compared to Hornady since Hornady max is 43.2 with a commercial case. I've always read that you have to drop a grain of powder when using mil-spec cases, so that would drop the Hornady value down to 42.2 grains of IMR4064. Supposedly it would drop even a little more if using a primer such as CCI#34.
So anyway, I'm a little confused and would appreciate any insight others have to offer. I'm trying to work up the following load and don't want to overdo it:
150 grain bullet
2700 fps velocity
So what would/should be the max charge? Is 43.0, 43.5, 44.0 grade of IMR 4064 too much?
I use a charge of 43 gr. under a Hornady 150 FMJ , I would start at 41 and see how your rifle shoots.
Don’t look for pressure signs, compared to bolt gun ammo these leadings are very mild and weigh your cases. You won’t believe the variation in weight and don’t believe military are the heaviest. Federal commercial gets that title and Winchester are the lightest. Most military falls in the middle to heavier side so I just load for that and save all the FC for high performance bolt guns.
I trim to standard, throw charges close and trickle to finish, seat the 150’s to the chanlure and slightly crimp with a Lee Factory Crimp Die. Any LR primer works but I like CCI.
These rounds shoot very sub 2” in both my 7.62x51 M1 and my M14’s. I give the same treatment to my ‘06 rounds for my Garands and I have one that shoots so well you can cover a full clip with a quarter at 100 yards.