Single trigger repair
 

Any recommendations on a gunsmith? This is the Parker trigger on a Trap Gun.

Try Dan May. He fixed a Super Fox Kautzy trigger

Like Mills said, Dan May of the Miller Single Trigger Co. and Classic Gunstocks.

The DelGregos fixed one of mine.

I also recommend Dan May. This may make some members cringe. I asked Dan May to alter my 12 ga VH, with Miller single trigger, from a three way safety (forward position fires right barrel first; middle position is safe; and rear position is fire left barrel first) to a two-way safety (forward fires right barrel first, back is safe.) My rationale was every shotgun I hunt with has a two position safety and rear is always safe. I'm getting older and don't wish to mess with my muscle memory and accidentally place the safety in the rear position thinking it's safe only to have it be in the fire left barrel position and thus, not safe while I'm hunting birds. Hope this makes sense.
In any case, Dan did an excellent job and did it in a way that it could be reversed when I pass on and someone else has custody of the Parker and wants it in the original configuration.

I have an old LC Smith (1890) with the "Trap Safety", in which the most rearward position is a non-auto safety position. In other words, the slide does not move into "Safe" when you open the gun.
It makes you think a bit when in the field.