Lstansel

I shoot the dpms sass. With the 1/10 twist I've stuck with 175 grain. While I reload for all my weapons I like to try what's considered the most accurate factory ammo to compare my loads. I've shot federal GMM in 175 gr. Black hills in 175 grain. Hornady super p in 178 grain and American ballistics ml118lr in 175 grain. In my rifle the federal GMM always came in first, but all was fairly accurate keeping under 1 " when I do my part. I use bipod and small bag for support under my wrist. Would do better with full bench rest but I try to keep it real with this weapon. I've also shot privi and a couple others but they didn't come close. My reloads do much better, but the question was about factory loads. While the hornady super performance in 178 grain comes in third behind fed GMM and black hills in accuracy for me, it was the only one to break 2600 fps in my 18" barrel. That is considered somewhat of a standard velocity most 175 gr try to hold to. In a bolt sniper rifle that is. So with the hornady you can obtain close to the expected bolt rifle velocities of standard ammo in a 18 inch barrel. But like I said I lost some accuracy.

I have the DPMS SASS which has a 1/10 twist. My most consistent load with the 175 Sierra match I use is 45.3 gr varget in lapua brass seated to 2.800 oal. CCI BR2 primers. I knock the charge down to 45 gr for some military match brass although it's not quite as accurate as the lapua. Using bipod and only a small bag under my wrist I can consistently shoot 1/2 to 3/4 " groups doing my part. I don't fully bench rest my rifles when shooting because I want them to shoot like I use them in the field. In my M1A I use a light 42 gr AA 2520 with 168 match. The same load I use in my bolt 308 varmet special. Very accurate in m1A but powder is dirty compared to some. I love aa2520. Meters in dispenser great and extremely accurate but I wanted to work up a 2600fps load for the SASS with 175 gr rounds in 18" barrel. Varget achieved that for me with great accuracy.