I had my 300 RUM rebarreled with a Douglas XX Premium. Upon initial load development the old brass (twice fired) used in the old chamber was very sticky. I full length sized and chambering was not a problem. I thought the chamber was too tight so I had it touched up a bit. The new chamber is well withing specs. New brass does not exhibit the same problem so I do not think the chamber is out of round. New brass it very accurate and after firing one time does not exhibit the same problem either. Is the brass from the other chamber weak and stretching too much? I cannot find any external dimensional differences between the brass that sticks and the brass that doesn't yet I know there must be something. The old chamber was larger, I know that. Is the brass just getting weak after only two firings?