use the old stuff
I learned the hard way that most of the stuff on the market for sale these days aren't up to the original specs. I learned from one of the best, his name is Forrest Davis. I bought a bunch of new parts and went to him with them. I ended up returning all of them but one. The one I kept was the extended safety. He uses match stuff from when he was in the Air Force and worked on the pistol team's pistols. I wish I could buy all of his supply up for sure.