with a 1/12 twist, this is the ammo you want;
plain blue box, plain 55 grainers, black hills. 50 rounds per.
plain jane remmy/umc white/green box, 55 grainers, hollow points, then solids.
wolf 55 or 62 grainers, the 62's actualy show more potential, but you will get a flyer now and then; they are close to max weight for that twist rate.
Best of all, if you can find them, and they won't be cheap, winchester
45 grain varmint/hollow points, big white boxes, 40 rounds per.
This is my cz 527, 1/12 twist; proly more accurate than your rifle, but should be comparable. these targets were done at 100 yds, off sandbag rests, front and back. The winnies , yes they are actually 1 hole shot groups.