I did a complete disassemble to duracoat and now the slide till not go back on. The feed ramp of the barrel is hitting the top of the locking insert. The insert looks like it is seated all the way on the bottom of the frame. Any ideas?
Yea this^^. Check slide fitment without barrel. Also check the barrel installed without slide.If I were to take a wild guess, I would suspect fairly tight tolerances and too thick of a coat of duracoat somewhere or another.