I am a machinist, and when I got my Suppressor stamp from the ATF, I was going to build my own from scratch. Then I found SPELAB and didn't realize how well made these silencer parts were, but with their great pricing, I just ordered a couple too see what happens. Well, I can't machine them any better on my equipment, OR any cheaper! The tolerances are spot on, the threading/knurling is perfect. They saved me a ton of time and $$$, and my silencers perform as well as any you will go spend WAAAAA...