This is a discussion on 4064 and the 168gr SMK within the Ammunition forums, part of the M14 M1A Forum category; At this point I'm not shooting past 300m using the 168 SMK and Federal brass with IMR4895.
Got decent results.
I want to switch to ...
I've been working up some alternate loads for the Socom and the 168grn Nosler, my test load for IMR4064 was 36.0grns but only clocked about 2050fps or so out of the 16" barrel. I was going easy because I didn't want to beat up the gas system, so you should be OK starting a little higher.
IMR data gives 41.5grns as a starting load under the 168grn Sierra.
41.5 grains of IMR 4064 in an LC case and topped off with a 168 grain SMK would be pushing things a bit fast for my taste. The Hornady reloading manual lists 41.6 grains as the max recommended load in their M1A service rifle section but they are using Hornady cases and their brand of bullet and that will make a difference. I would expect to use slightly less powder when using an LC case but bullet length will force you to make slight changes in powder charge weight.
I would prefer about 40.2 grains to keep my chamber pressure down even though the muzzle velocity would be a little slower than I like it. This is assuming that the cases were trimmed to about 2.005" and the bullets were seated to give about 2.81" overall length. Just remember to start low and work your way up in powder charge weight. Case volume has a huge impact on these numbers and when others give you their load data you have to remember that they may be using different cases, trim to lengths, and seating depths.
One of my best loads has been 41.4 grains of IMR 4064 in WCC brass, trimmed to about 2.006", an OAL of about 2.83", a WLR primer, and topped off with a 168 grain Hornady A-Max bullet.
Never had a pressure issue with 42 grs of 4064 in all the rounds I've reloaded. From what I understand, it's pretty much a go to load for 4064. The following link provides some useful info. You may have to join to see it, if you're not already a member over there, but there is a lot of useful info for all things competitive shooting there. HTH
One thing I've noticed.
My .223 load for my RRA NM A2 was very easy to come up with. Very accurate.
The M1A and Garand are more problematic.
There is another factor when you throw in the AR word in the M1 and M1A discussion. In highpower shooting, ARs for the most part will let you commit some shooting sins and get away with a decent score. The M1s and M1As will blow you out of your position with your first shot if you do not have a solid postion.
The above statement holds true even shooting from the bench. You hold that M1 or M1A with varying shoulder pressure and grip, you can see the groups go all over the place.
Sorry for the side track there. Back to the original topic, 4064 is it.
Do your load development for your system, start at 41 and work up at .3 increment. watch for pressure. One of my M1As shot the best at 43, another at 42.3, and the another rifle at 44 (with Berger 168s and 185 Bergers) and the rest are all with SMKs.
The 42.3 load was convenient because that is the same charge I use with the 185 Bergers. And, the same load for my McCoy built M1.
Mostly for short range I just use 135 FB Berger bullets with 44 grains of 4064.
The M1A/M14 data is towards the end of the "Reloading Stuph" link.
Those loads look pretty hot for military cases. I think they are in commercial cases. I know they are based on muzzle velocity. The Hornady service rifle load data is based on gas port pressure. It is in commercial cases but uses the Hornady A-Max bullet which may fill the case more or engage the rifling more than the Sierra Match King.
It's pretty hard to get "too much' IMR-4064 in the 308 case. The traditional match load is 42.0 grains of IMR-4064 in a military case with the 168 grain SMK. It is a maximum effort match load though, so it might be a bit warm. The Federal 168 grain OTM service rifle load is 42.5 grains of IMR-4064 in a commercial Federal case with the CCI #34 primer. The case capacity of some commercial Federal cases is about the same as LC military cases but the case heads are thinner and the case walls are thicker and the brass is softer. I still get higher velocities with LC brass than Federal brass though. I try to avoid using Federal cases and haven't loaded any in a long time.
The NJ reloading website I pointed to doesn't specify which cases were used. 43.0 grs of 4064 may indeed be too hot in a military case, I don't know, never tried it. I can tell you that with 42.0 grs. in my LC M118 cases, I have never seen a pressure issue and the accuracy is very good. It'll hold the 10 ring on the SR and SR-3 target with a decent X count all day long outa my rifle. As other's have stated, start low and work your way up slowly to find the correct load for your situation.