KSC Glock23f issue

[rampage]

HELP! if anyone can help it would be much appreciated

I have a KSC Glock 23F:
Firefly Rocket Valve
Metal Slide
Upgraded Guide Rod + Spring
Only one of my mags has a High Flow Valve

When shooting The gun will cycle and fire once or twice then will only cycle half way. Slide only comeback half way and will not load a new BB in from the Mag. I am using Propaine + Adaptor to fill mags, I lube the mags and tank with silicon oil.

This gun has never worked for me. When taking it apart I lube the Piston seal, Outside of the blowback valve, 2 springs are in perfect condition, everything glides nicely without sticking.

Any Ideas????

Thanks

[hattrick]

Firefly rocket valve seated improperly, just a guess.