KSC USP problem
 

Im new to GBB so bear with me.
Every time i load the clip and fire it unload's the gas in one shot.
The slide has no tension but it does not reload.

HELP PLEASE

it sounds close to the same problem i have. and i have tried just about everything to fix it.

Have you been using Tetra-gas? or Dif-gas? Difloreuthane (sp?!) wears seals, ultimately destroying yer GBB. I've been using Tetra for 60 fills, and have yet to experiance a problem.

Read up on the cooldown effect.

It was the blowback chamber seal. It had come dislodged from it's "groove". I've seen it happen to USP's in the past. Takes literally about 5 minutes to fix.

Which part is this exactly?

I've been experiencing the exact same problem where all the gas in the mag is vented in the first shot.

Taking the USP apart reveals that nothing appears out of place.

Any help would be appreciated.

Its inside the piston, requires you to remove it from the slide.
You will find a black ring underneath that has lodged its way to the back. Simply putting this back into place will fix it.

Get some oil in around the firing pin (the thing the hammer hits that then in turn hits the mag's valve) and between the hammer and firing pin, then dry fire it a dozen times to work the oil in. This happens a LOT in GBBs that aren't well maintained/new, I've had it happen a few times ot my guns, have had it happen in friends guns, and there have been at least a dozen cases on here where "the gas releases first shot". Everyone of them has been fixed with oil. If the problem is as mcguyver pointed out, that's one option, the other is oil.

Literally what is happening is the firing pin hits the valve, the slide starts to move but the firing pin sticks and doesn't retract, causing it to sit on the valve releasing all the gas.

I got it.

I missed it the first time around because it's black and on black and the lighting in my room is poor.

Thanks.

But now my mag has developed a leak that isn't solved by drowning the valves in oil.

Any ideas?

Where is the leak.

Canadian Tire Blue Gasket Sealant (automotive) works great on GBB mags if you know where the leak is coming from, just gotta take that part out and bead the gasket sealer on, then let it sit 24hrs before putting gas in.

To avoid leaks, always have a charge of gas in our mags. Period.

The silicone drowning seems to have resolved the leak, but it was coming from the output valve.

But is that gasket sealant permanent? I mean will I be able to remove the seal if it becomes necessary?

For the record, I always keep gas in my mags. It's only when they spring leaks or I empty the mag through firing that they wind up empty.