GBB mag venting straight through on fill- solution?

[Vyking]

There was a wonderful guide by AI that took you through all the possible problems with GBB mags and I'm sure this was on there but alas I lost my copies.

I have the new ASG branded Cz75 GBB shell ejector - not a skirmishing weapon, just a fun plinker and a work tool. It was absolutely fine for a good few months then two days ago while teaching my better half how to operate it, she decocked the hammer as you would do on a 1911 and it began venting gas everywhere. Since then the mag has refused to hold a charge of gas. When you turn it upside-down and fill it, the gas all shoots out the top valve and retains nothing. The usual fix of silicone oil doesn;t seem to be doing much. What's my next step chaps?

[daladzor]

Re: GBB mag venting straight through on fill- solution?

It sounds like the top valve is stuck open if its just venting as soon as you fill it.

[loki7491]

Re: GBB mag venting straight through on fill- solution?

To be clear.... when turned upside down and filled from the fill valve (in the base of the gun) gas vents from the top of the mag, which is now at the bottom because it is upside down?

If this is the case, you most likely have a sticky or damaged valve on the back face of the magazine (the one the hammer hits)

Remove, stir it in a mug of boiling water. Once it is cool and thoroughly dried silicone the hell out of it and check operation. I have saved many valves using this method.

[Vyking]

Re: GBB mag venting straight through on fill- solution?

loki- you describe exactly- I'll have a bash at that then