Might add that it doesn't work the other way around, in that most .308's have a 1/12 twist, so if you want to use 220 grain bullets in a .308, you may have some stability problems and resultant yaw and inaccuracy with the extra long bullets. Rugers are 1/10, and solve that potential problem. .303's are 1/10 also.

I have never heard of a 220 grain factory load in .308 Win, 200's being the heaviest load in factory ammo.