I have attached front sights with JB Weld and had very good luck. Clamp gun between two blocks of wood in a vise. Clean both parts very well with a strong, non oily cleaner. Brake cleaner works good. Put a strip of masking tape on all 4 sides pf the slot in the barrel, right up to the edge. Mix the JB and apply a thin bead to the bottom of the slot, put the sight in. If any JB weld oozes out simply remove the tape carefully and it should take the ooze with it. You actually want a liitle ooze all the way round to insure that the sight will hold. Line up the sight, then resist the urge to touch it for at least 24 hours, 48 is better. any additional ooze can be filed carefully with a small needle file.