G&G GC16 Wild Hog - Feeding Problems

[Batflap]

Recently bought a second hand GC16 Wild Hog, but there's some feeding issues where every 4-5 BB's it fails to chamber the next BB or two. I've heard G&G guns are picky with which mags they use, however I've tried it with a G&G hi cap from my F2000 and it still presents a problem. I've replaced the hop rubber as well to no avail. Wondering if the piston isn't retracting properly? There's also a spring-like resonating sound when it's fired, if that's of any relevance?

Wondering if anyone else has encountered this issue and where I should begin?

[sj_asc]

Is the gun stock?
Its possible that there is compatibility issues between an aftermarket nozzle, tappet, or chamber.

Tappet fin may also be warn and or sector tappet cam (if non oem) may be slightly off spec.

[Batflap]

I'm not sure if it is, the guy before me said he sent it off to get fixed and it didn't work. I'll potentially take the gearbox apart and upload a photo here so people can get a better look. I'm confident taking v2's apart but question my ability to diagnose the problem

[sj_asc]

That would be helpful, mostly for OEM parts identification.