You mean the little FO rod breaks off, (usually at one end), and the rod falls out?
If so, each time you clean the gun, give the rod a little wiggle test, front to back. It cannot have any slop in the sight housing. If it has slop, it'll slide back and forth with each shot and break off one mushroomed end.
If you feel slop, bring out a lighter and melt one end so it's tighter against the housing, and will not move.



























