Re: 243 win loaded neck dimension
Just a quick .02 here.
I don't think I'd have my chamber cut for factory brass. Find out what the minimum amount of neck turning required to clean the necks up is and then chamber for that loaded dimension. It's more work, but more accurate also and you won't have to worry that you'll wind up with a round here and there that won't let the bullet chamber properly because of the close tolerances.
All it takes is One Good Shot!