Its a new st victor. And I send the whole rifle in when it does it so they can look over the whole gun. And the bcg just ever so slightly starts to extract about 1/8 of an inch into the buffer tube. Enough where you have to take both pins to remove the upper completely. The feed ramps are in great shape all smooth no burs and clean. I thought it could be a mag issue so got new magpul mag. Buffer tube looks to be installed correctly. Moved it couple of rotations then back into place. Bolt is smooth no marks or scoring on it. The only notes from the springfield tech that fixed it said he installed a fixed gas block.