I took my lvl 10 SFL out on the field and everything was going pretty well at the beginning. I'm running 1.5 carrier with 2 shims and the shotest spring in the kit. I would run the medium cut spring but it leaks out the back at around 230 FPS. I have a new regulator piston on order so hopefully that will help. Without going into a great amount of detail I went through every kind of E-mag related valve problem imaginable, bolt-stick, full auto and finally air gushing out of the back. Finally as I was about to stab myself, Matt Davis of Jax Warriors showes up. Between the 2 of us, and a repair kit we managed to get it shooting 290 without leaking. At this point the bolt is still hitting pretty hard. I can stop it with my finger if I brace for it but if I'm not ready it will pinch you finger pretty good between the bolt and barrel. But at this point, I'll take it because I can finally play. I go out and play my first game. After about 4 minutes I start hearing a hiss down the barrel. It starts to get much worse as the game goes on. finally by the time the last guy is gone my SFL has air rushing down the barrel and my tank is almost out. I flick off the tank and go break down my mag again. This time the back half of the bolt piston has shot off and gone down inside my valve. I break down the valve and fish it out. I take some blue loctite push it back in the bolt as far as it will go and pack up and go home. Hopefully the loctite will hold the bolt together and the new regulator piston will allow me to use a longer spring and soften the bolt a bit more. Right now if I were to stick my tongue in there I would lose it.