GunAddict1962
Inactive
Ran into a problem with my latest AR build. Bought a new 1-8 twist 20" DPMS varmint barrel from Midway. Everything came together fine. No obvious headspace issues. Barrel looks nice inside. Immediately noticed though that unfired rounds would stick in the chamber. Not every round, but about 2 out of every 10. Takes a good rap on the charging handle with a rubber mallet to move the BCG. On every ejected (unfired) round, on the bullet, about .05" above the lip of the case, there's a very distinct ring imprint. Noticeable on nearly every ejected round, significant on the stuck rounds. A crisp ring, with no visible land marks. No free bore in this chamber? Tried 5 brands of factory ammo 50-62gr and 3 different reloads 50-68gr with bullets at different seat depths. Nearly every type would eventually lodge tight in the chamber. It takes seating bullets way deeper than they normally would be seated to prevent this. No signs of dangerous pressure levels on spent brass, but really poor accuracy--2 inch groups at 100 yards. No consistency. Fliers every 3-4 shots. (In case you are wondering, I didn't really find the problem until just about finishing up on the range.) I'm not a smith, but I've been around guns a long time. Am I interpreting things right? An out of spec chamber/free bore?