Originally Posted by 1luckeyt/a
I measured the sized case mouth and it's I.D. was a little under .306. When I measured the bullet it was .309. Is 3 thou to tight?
If your SMKs are truly measuring .309" then they're oversize. Did you pick these up as rejects from the factory? The specs for the .30 cal SMKs call for a max of .3084" which shouldn't be significantly different from the Noslers, Hornadys or anything else here that's run to SAAMI specs.
I'd suggest you take another look at the chamfering process, and possible the steel wool apporach that Shummy described. Anything that eases that transition of the bullet entering the case mouth smoothly is probably going to be time well spent.