Install a new extractor spring, gold color version is best. Look thru the magazine will and slowly pull the bolt back. See if the ejector tip tracks...
Everything from the match kit will work in the USPc except for the trigger. Drilling/tapping the current stock trigger will not work either. There is...
Whats the height of your bolt carrier? Yours might be a modified full auto carrier, might ba a little taller than a semi version, meaning the bottom...
3 things, you can pick up a surplus safety switch where the detent spring is broken in or Dremil in a ramp(s) on the edge of the dentent hole in the...
A little smoother and lighter on the sear spring. Most DA "grit" feel comes from then interaction of the trigger xfer bar interfacing with the hammer...