I have some gator gas checks that are supposed to be for the .348 Win. I have an accurate bulled mold for casting .348 gas check boolits. The gas checks fit the shank properly. The problem I am having is seating and sizing. I made my own lubrisizer die sizing to .348. The force required to seat the check compresses the boolit and shaves the sides. Band diameter of my boolit as cast is .349-.350. Diameter of the gas check is .356. Is this the proper size for the gas check or is it to big? Any ideas or suggestions would be greatly appreciated. I may possibly make another sizing die or two in larger sizes.