Every rifle is different, but I would think that if you are keeping the brass specific to a particular firearm, whether it's semiauto or bolt, then bumping the shoulder would probably provide reasonable reliability and would work fine for 99% of people. If you're talking about life or death "every round needs to chamber 100% of the time" reliability, then I'd be using ammo that leaves more tolerance for fitting in the chamber. When starting with unknown brass, I always full-length size for the first reloading. Load some up with a shoulder bump and see if you have any reliability issues...if not, load 'em and shoot.