Well, there's no brass key stock within a million miles of North Carolina......guess I'll haveta mail order. But I had some left over aluminum callin out like a helper lookin for a project so, sawed off a chunk a bit over 5/16" square and about 1 1/4" long. Center drilled it......cross drilled it....thinned and tapered it and ...... it fits in as the filler blank to house a spring and plunger to keep the trigger under control.
The center hole I drilled is .190" diameter and the spring I chose is somewhat smaller than that in diameter. Still too long but I'll trim it later after makin up a plunger for the end of it.
For now, the cross pin is undersized. I'll pin it with a fitting piece of drill rod later.
Looking down from above, I tapered the rear down and short. There has to be clearance for the hammer spring and strut and no need to have this hunk of metal in the way. Might be some light fitting later....for now, just the basic install.
Once a plunger is made up, the new trigger filler block will hold it all in place providing the same type of trigger return capability as you can see on the 3 Screw.
And just in case I get real energetic....this here maple is supereyebunger curly.