I bought the factory ammo, shot it and it shot dimes! But out of my old oem Browning Abolt it was slow. 2800 or something. So I used the Hornady brass, CCI 250 mag primers and 72.5 grains of H4831. This is HOT! It crunches a little. I took a dremel tool to my magazine and seat mine at 3.60 COAL. 3000 fps and with that goofy BOSS I tuned it right in to tiny groups. It shoots 4 inch groups at 700 yds which is as far as I have stretched it out on paper. The target was me shooting and adjusting to be dead on at 200 yds. The last 5 are all in one hole. Good luck.