with a lighter bullet such as a 245-295 powerbelt, my winchester was a powder hog and needed 120 grains RS loose powder to put them into 1" 3 shot groups. Anything less and they opened up quickly. with a 348 powerbelt, 385,410 grain great plains, 80 to 90 grains RS put them perfectly. Just have to play around with new bullets, powder, powder charges until you find something you like.