Blackhawk cylinder pin comes loose

[rallyhound]

I bought a used SBH 44.
Shot it and pin comes out , binding the cylinder.
Shop gave me a free upgrade. new pin with a allen set screw to lock pin in.
Still comes loose even though i tightened the snot out of the set screw.
Can i fix the plunger myself or do i need to send it in?

 

[Dfariswheel]

There are two "Fixes"

One is to replace the plunger and spring, since these do wear, and sometimes the spring gets weak.

Two, is to chuck the base pin in a lathe, or even an electric drill, and use a small, smooth-cut round file to slightly deepen the groove the plunger lock into.

Deepening the groove in the base pin is the most effective fix, just don't WIDEN the groove, don't SLOPE the sides of the groove, and don't go to deep.

This gives the plunger a deeper groove to lock into and this usually stops base pin movement.