Sounds like you had a fun day with your War Baby! The problem could very well be the recoil spring - easy replacement and inexpensive part. Actually, I have a few extra if you want to try that. I'm in northeast PA so it's a short mailing distance. Did you check the gas piston nut - the one you said was loose? That could also be a problem but if it's tight, it's probably OK. It might also be dirty gas piston, but my bet would be in the spring.