[lte82]

I am having some issues with getting my load figured out for my ar-10, and I am wondering if my problem could be with my powder.

My load is:

Remington R-P brass
Winchester magnum primer
168gr smk
42-45gr imr 4064 (loaded in .5gr increments)
2.806 oal

My groups are 1.5moa with the 45gr but out to 3.5moa with 43.5gr.

A guy at the range asked me to try a handfull of his loads (168 amax over 41gr aa2520) and i cut a hole the size of a dime with 5 shots. Probably .3-.4moa.

Im wondering if maybe my powder is too old... its 21yrs old but was still sealed / unopened as of last week. The primers are also the same age... It was stuff my dad bought around the time clinton was elected and I wanted to burn that up before I got anything new.

What do you guys think?

[Lj1941]

It is possible that your particular rifle doesnt like 4064. Are you using a powder measure or weighing each load? My measure is horrible with 4064 ,making me weigh each load.

[30Cal]

Weighing charges usually doesn't make a measurable difference on paper until we get out past 300yds.

If the powder/primers were stored someplace that fluctuates wildly, then yeah, it could be a little of that.

How are you seating your primers?

How did you come to pick 2.806" OAL? Odd number. Was that one cartridge you measured or are you tweaking the seating die every time to get that?

[lte82]

I throw the charge light and trickle it till its dead on.

My ar-10t and my dads standard ar-10 reproduced the same results. Could be the gun / powder combination but a lot of ppl use the same combo with good results.

Frustrating... I guess I will crack open a fresh can of powder and use some new primers to see if it makes a difference.

[lte82]

Seating the primers with a Lee hand primer.

The powder was stored in a closet inside an air conditioned space... I did notice a few reddish grains, but not sure if that matters. I only saw 5-6 that looked like that out of the loads we made.

[30Cal]

If it's got AC it should be good essential for decades. I doubt it's the powder. You could send it here if you have doubts though.

I just noticed you're using a magnum primer. You don't need that. Try a large rifle instead. Make sure they're all firmly seated the same.

[rsnell]

I agree with 30cal. A magnum primer is not necessary for your 308. Try a standard rifle primer.

Bob

[lte82]

Ill give it a shot. I dont have any on hand so it may a be a while till I get some.

What do you think about going down to 40-40.5 grains with the magnum primers? Maybe im way too hot since I am using the magnum primers?

[jack44]

Try VARGET.

[FROGO207]

Might be an improvement with a slightly lighter load, I would try it with your components. Also if you can get your hands on some aa2520 you could try that and work up to the load he used. Might be the bullets and barrel are at odds also. As I have learned not all bullets work equally well in all applications. That it bothers in two rifles seems to be significant. Again lighter loads were where I would start if it was my ammo. At least you have everything to try that already.:)

[Kachok]

Try VARGET.
+1 bought a pound to try in my 308, shot so well I am going to get an 8lbs jug so I won't have to worry about lot variation for a long while. BL-C(2) is supposed to be another really good one in 168gr, I cannot vouch for that though since my 308 does not like anything heavier then 150s (1:12" twist)

[kelbro]

42.9 IMR4064 and a 168gr SMK works like a laser in two 308s of mine.