Richard.......Do yourself a big favor and send the gun the Doug Braker, The Gun Doctor for this repair. Doug did an excellent job on my DB-81, was VERY reasonable, and his turnaround time can't be beat. Fitting a new locking block is not a job for the average shooter. It's not that expensive to have it done by a professional, and that is exactly what Doug is........Just my experience.....Dan Thome (Trap2)