Umarex MP7 not emptying magazines with full gas load

[Jay_Swan]

Hey everyone,

Long story short, my buddy bought a used mp7 from a friend and the first times I tried it it worked fine even at low temperature. Now that the summer is here we played a couple games and he noticed that he is not emptying a full mag with a full load of gas. After a few mags the last one shot once and the mag emptied itself of all gaz in the locked back position. In the first shot he got 420 fps then 400 then 370 then 330 all the way down to zero on all of his mags so I am guessing that the problem is in the gun itself.

I have not stripped the gun apart yet as to find some advice on a possible solution that you guys would recommend first because it will be the first gbbr that I take apart and I do not wish to screw this up. Maybe some seals are worn out, or maybe too much gas is delivered in the blowback, maybe the nozzle is broken... I will change the seals even then as per normal precaution but maybe some enlightened fella could show me the light :cool. Thank you for your help!!!

[cetane]

Try a fresh bottle of propane or greengas and make sure your filling it fill valve facing up. Could just be an empty/near empty bottle of gas

[Jay_Swan]

Well I bought two of them so that is not the problem even do it could have been that xD but the valve on the up side I will try tonight

[Jay_Swan]

Still the same result...

[BioRage]

Try a different adapter, make sure mag is room temp as well.

[Danke]

For sure that sounds like a fill issue. I have a half dozen of those mags and they're the best gas mags on all counts. Filling, consumption and long term remaining sealed.

[Jay_Swan]

Thats sounds quite right I took the time to listen and the fill only lasts 2-3 seconds then it seems to stop filling