I have an brand new Armalite with a 24 inch Oly SUM barrel, 1 in 8 twist. SAAMI chamber and JP trigger. It has a 6x18-50mm scope on it.

The only AR's I've shot up to this point have been carbines and shorties chambered in 5.56 Nato. All my shooting experience has been of the plinking variety.

What would be a good Factory Ammo choice for breaking it in?

What about these choices from Black Hills?

.223 Rem. 77gr Sierra Match King HP

.223 Rem. 69gr Sierra Match King HP

.223 Rem. 75gr Heavy Match Hollow Point

Am I going "too heavy" or not heavy enough?

Would I be wasting $$ to use either of those to break it in?

Or something different altogether?

Thanks for any info......I'm not sure where "I'm going" with this rifle. Maybe varmints and Coyotes, or some long range paper. It's all new to me. I do know that I am going to get a bipod for it. It is a BEAST.

R

Anything from 62 to 80 grains should work well in a 1x8, per Kuleck & Duff.

If you want to stay inexpensive while breaking it in, try .223 FAE or Win 62 gr FMJ.
Both are quality rounds and won't break your wallet on break in. Maybe $4.50 per 20.

After break-in, try a little bit of everything, and see what gives you the best results before you make an investment in any one round. One theme that seems to be repeated is that every rifle has its own best ammo. The fun comes in solving that mystery.