Tuning Air force texan.tx2 50 cal valve problem ?????

I need a little help. .I shot my texan.until.it had I guess a valve. dump. which empties all the air from the tank m. Which is fine. After I went to refill.my gun and it would not hold air. I could here something rolling around in the tank. .My question is could.I of.blew the burst disc.and never new because the tank was never without pressure. Second.I have been trying.to get a hold of.air force for days emailing and leaving messages.with no reply. I just want to.fix.My valve. Any help.is appreciated I am still new to air guns and I'm learning and making mistakes. Thank you all


 
Have you tried Cocking the gun b4 filling from zero start pressure?

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I took the top hat off the valve and the o-rings were fine. I took out the stem and there is a small metal part that is supposed to be in the back of the valve. That was the metal part rolling around in my tank. I would love to see a diagram of the valve so I would now what parts are inside. Maybe airforce will get back to me. Thank you again