I purchased a Savage 12 FCV 22-250 a month ago. It took about 6 different powders and grs. for my load development. I achieved what I wanted with 35gr. Varget, WW primers, 52gr. Sierra HPBT #1410, (any other primer opens the group up by inches, don't know why. I'm very happy with the rifle and the load. This will group 5 shots in .5" group, sometimes .375" if I really do my part.

My question is, why does this rifle not shoot 50 gr. bullets as well? Is the 1 in 12 twist not good for 40gr. or 50gr. bullets?
I don't really understand well the rate of twist needed for a particular weight of bullet.
Any help please. Thanks.