Just picked up an M1A a couple weeks ago and wanting load suggestions for 165 to 180 grain bullets. I know that some propellants are not suitable for the operating rod. I have heard that IMR 4064 is matched pretty well to the M1A's gas system. Anybody here load for the M1A ? What powder ?

I used to use 4064. Now I use Varget exclusively for almost all my 308 loads, not just the ones for the M1A.

For the factory sights, 165 gr is about as heavy as you can go and still be on target past 300 yards. I generally only shoot 147gr or 150gr out of my M1A and my FALs. I think the 150gr is about the perfect weight for the 308. The FALs have a 1:12 twist and a 180 gives horrible accuracy. I forget what the twist on the M1A is, but 150s are what I get my best groups with.

There are several M1As on the line every month at our NMC matches. You are correct that IMR4064 will work well. Same is true for IMR4895. Hope this helps. Take care...
Joe

I agree with Joe. All the best...
Gil

Thanks guys, I believe I will go with the 4064 and 180 grain bullets. The M1A has a 11" twist and I have had pretty good accuracy so far with 180 grain factory ammunition. I like the heavier bullets for bear and moose, which was the purpose for buying this rifle. A reliable, no nonsense self loading "boat rifle" for river excursions.

IMR 4064 will do what ever you need done.

roklok:

PM sent.

Shouldn't be shooting anything over about 165gr with the M1A regullary unless you got a NM grooved piston to remove the pressures in the gas system of the heavier ammunition.

Dimitri

Dimitri, I have heard that a few times but never saw it in writing. I studied the manual from Springfield and it says nothing about bullet weight. I did think once I started loading for it I might substitute premium 165 grain bullets for the 180's.

Roklok,

Remember Gas driven semi-automatic rifles have issues with the pressure curve in the barrel, powder and bullet weights effect the pressure curve.

110gr ammunition such as the Hornady TAP ammunition will not allow a M1A/M14 rifle to cycle properly for example. But shooting a diet of 180gr ammunition will cause problems with your op-rod and can bend it.

Here is a Piston that will alow you to use 180 gr ammunition in your rifle (originally intended to shoot M118LR 175gr Sierra Match Kings), but be forwarned, it will cause issues with shooting 150gr ammunition as there will not be enough pressure to cycle the lighter loads.

www.sadlak.com/si_rifl...stons.html

Dimitri

Dimitri wrote:

Remember Gas driven semi-automatic rifles have issues with the pressure curve in the barrel, powder and bullet weights effect the pressure curve.

That's why I love adjustable gas systems.

There used to be an aftermarket cylinder nut that allowed an M14 user to adjust the gas pressure. I don't remember who made it, though.

Phil,

Perhaps your thinking of:

www.midwayusa.com/epro...t=11082005

Ether way I've heard some mixed reviews on the plug.

Dimitri

Some powders that work well for your application that come to mind are 2520, 748,varget, 4895, 4064, and blc2. I believe benchmark might work well too, just never used it yet in a 308 gas gun. The op rod issues you mentined doesn't really apply to the two piece op rod system of the M1a. It is however a big issue with the one piece op rod on the M1Garand. With Slower powders like IMR4350, the pressure curve is still real high when the bullet goes past the gas port. This high pressure can apply so much pressure on the M1garands op rod that it can bend it. On the M1A, it can only push the gas piston so far and it bottoms out. Once this happens it cannot push the op rod any further. However, it is stilll best to use the faster powders that I listed because the flame temp will be lower when the bullet passes the gas port and won't burn out the port as quickly.
Hope this helps.