Mrod valve

I was shooting the other day and could not get a good group, so I broke out the lead sled and was still shooting studs. I took it home and set up the chronic and started a string. The second shot all the air discharged out the barrel. I removed the valve and found nothing wrong with it. What else could be wrong with It? Thank you.
 
Did you take the valve apart and look very closely at the rubber on the pin to see if it was cracked or somehow separates under pressure and loses seal. Possibly a piece of dirt or debris got on the sealing area and wouldn't let it close. If you put some pressure on the assembled valve now does it seal ? I'm still betting the pin and rubber need to be replaced.
 
"my 22 Mrod did the same thing.it has a a WAR valve.i sending it out to be fixed.fmglass"I was shooting the other day and could not get a good group, so I broke out the lead sled and was still shooting studs. I took it home and set up the chronic and started a string. The second shot all the air discharged out the barrel. I removed the valve and found nothing wrong with it. What else could be wrong with It? Thank you.
 
I'm no genius; I am a long time competitive shooter but new to air guns. The fact is the same thing happened to me several weeks ago so I had to make the same repair ( in my case the rubber on the pin was crumbling and was obvious ) and am now learning to tune the gun. By the way the Bstaley tune made a world of difference for this gun !! Thirty five good shots at 850 ft/sec in .22 cal. Anyway good luck.

Roll'in
 
My Marauder .22 Rifle did the same thing. In a great rush of air, It lost all its air pressure. It was no longer under warranty, so Crosman wouldn't do anything with it - but they did give the phone number of a repair shop here in Ga (I live in Columbus) and I've sent if to them for repair. When I called, Roy, recognized my problem and said it was the "stem".

I went it to him, I should be getting it back shortly.

Bobby