I bought my JR in 9mm when they first came out, I ran 200 rounds of American Eagle ammo through it and it functions flawlessly. I bought a cheap Lee mold to cast bullets for it and have shot around 2000 rounds with 4grns of Unique and it has ran amazingly well with this load. I don't size the bullets, just tumble lube with Allox. Not even a little bit of lead in the barrel. I ordered the 45 conversion kit for it last March, and thats when I had a little trouble with it. The trigger wouldn't reset with the 45 kit in it, but would work awesome with the 9mm set up. So a quick call to EMF who manufactures the JR told me the triggers in the earlier ones were a little weak and it would require a different trigger to fix it. I told them I would order one up and put it in and try it, and they said they would just send me a whole new one in the mail. It arrived in the mail a few weeks latter and it solved the problem. I was really happy that they sent me the trigger for nothing, as it was out of warrenty for over a year.