Had a gunsmith do a chamber cast . Neck is .276 Earlier I couldn't insert a bullet into fired case. So I turned neck down to .273 fired the round and now I can insert a a bullet into fired case but its snug. Made sure I was turning necks all the way to end so as not to be creating a false shoulder. The loaded rounds chamber with zero resistance. Full length sized ,die is set correctly. Upon firing there is no resistance to when I begin to cam the bolt open. Its when bolt is fully camed open does the cartridge stick ?But firing same load in virgin brass there is ZERO problem ! On 2nd and 3rd firings of cases there are No shinny ejector marks on brass,no enlarged primer pockets and I'm getting well under 1/2 MOA groups buring 52grs of Retumbo behind a 105gr Berger Hybrid. Avg velocity out of 8 rounds was 3280 out of a 30" Brux bbl. This is 3rd bbl in this caliber on this rifle never had these problems with other bbls ? Gunsmith looked at Chamber cast and he said there nothing wrong ????