Only getting a few shots from Tanaka mag

[Moomike]

Hi all,

Just wondered if anyone had any idea what may be the problem with my Tanaka mags? Both my ten and 29 round ones only get a few shots before the gas has totally gone (the 10 round one gets about 4 shots and the brand new 29 round one gets 7 shots!) I've tried them with both propane & Abbey but it's the same either way which leads me to believe it's a problem with the gun itself.
I understand the fps will drop off as the mag empties (I am going for HPA rig shortly) but I just thought I'd get more than a few shots before it was pointless actually shooting it

When I fill other gas mags (like the G39 ones) it fills with gas pretty quietly and then at the end, once it's full, will hiss to let you know. These mags on the other hand sound almost like the gas isn't actually making it into the mag - it fills very noisily, hisses as soon as the valve is depressed - they don't leak, it they just don't seem to hold much gas at all.

I have tried pushing down on the fill valve & it pushes down fine, I have checked the striker plate at the back & it seems ok as far as I can tell, not too difficult that it cannot be compressed but not really easy to do either - the 29 round mag arrived this morning so it should be totally fine.

Am at a loss here so any help at all would be very much appreciated.

Cheers,

Mike.