I got the barrel on and did some test firing. I ran a 10 shot string and it went full auto for 2-3 rounds. There are a couple things that could have contributed so I'm not going to point fingers at the trigger. I went and tightened all screws down on the trigger again (one was only slightly loose, cleaned the gun extremely well and also cut down my buffer spring until it ran smooth (my buddy said he had read issues before pertaining to this but I don't know). The buffer spring was so stiff It was hard to charge. After all this was done, the gun ran flawlessly for a 20 rd test fire, half normal fire and half rapid fire. Time will tell. I will say the trigger feels great by the way.