I just purchased a Rossi .223 single shot, youth model, regular barrel with 1 in 12 twist. I sighted in with 55 gr. ammo at 25 yds, havent got to take any 100 yd shots yet. The group was in the 1" bulleye but i thought i would be stacking lead. I want to shoot coyotes mainly, and i was wondering if the 45 gr. would be better or if that has anything to do with the accuracy. Any ammo help is welcome.