I have 2 HK, a USP full size and a P2000sk (Both 9MM) and looking into getting a threaded barrel for my USP. My friend give me some reloads and one got stuck in the barrel. Lucky me nothing happen to me or the gun. So right now I am shopping around for a threaded barrel. I have done my research and going with a Jarvis extend barrel. I'm not sure what threading I should get. I want to get a suppressor in a couple of months. Is there any pros and con about getting a 1/2 28 vs 13.5x1MM? I would like use the suppressor with different handguns.