I don't understand why, even with a rough chamber finish, a belted case couldn't be removed easily. Especially when it's loaded with a normal, safe, max load. They all spring back a thousandth or more from chamber dimensions so extraction is easy. But a really rough one may be a different issue.
However, if neck only sizing is used, and a case has been reloaded several times, this might happen. Full length size them setting the fired case shoulder back a couple thousandths. Belted cases typically shoot more accurate resized this way anyway.
If the ridge a few thousandths in front of the belt's causing interference in the chamber, that may be part of the problem. You'll need a collet die to size that part back down to original body diameter for best chambering; accuracy, too. Get one from Innovative Technologies - Reloading Equipment
Done right, one can get 20 or so reloads per .300 Win Mag case. Use a full length bushing die from Redding or RCBS and no expander ball to minimize neck sizing work hardening the brass too much.