Slide will not reliably chamber or extract rounds. - Grey Ghost Precision Glock 43 Version 2 Stripped Pistol Slide

All rounds except for the last 2 of a magazine catch the firing pin. Either going in or coming out. Used all glock internals, agency barrel, factory barrel, nothing works. Working with GGP now to try to fix the problem but im 400+ rounds in and hours of frustration at the range. For a concealed carry gun this is an absolute no go.