G&P M4 possible piston/gear issue?

[Reaperman]

I've had it about a year with no issues, stopped firing today and still goes through shot cycles on semi and full auto but sounds like air is escaping and a bit of a grinding sound too in the background which doesn't sound ideal...

Any ideas? I'll take a video and post later maybe, could it be 101 things or are there 2-3 things to check first?

Thanks

[jonny lovegrove]

Re: G&P M4 possible piston/gear issue?

a video would tell a thousand words, so long as the audio is clear.

[Reaperman]

Re: G&P M4 possible piston/gear issue?

10-4. As I typed I though that it was a tad difficult to describe but something definitely busted I think and hopefully fairly easy to diagnose as the sound is quite distinctive.

Cheers

[Reaperman]

Re: G&P M4 possible piston/gear issue?

Got home (after work airsoft demo) and checked all the basics and turned out I had one badly mishapen bb seriously stuck in the barrel. This thing was egg shaped! Load of blowback obviously caused the noise and no fire but all cleared and good now.

[jonny lovegrove]

Re: G&P M4 possible piston/gear issue?

Ah that horrible noise would be the piston then

[Reaperman]

Re: G&P M4 possible piston/gear issue?



Happy to have it sorted with zero expense, it sounded bad. Up yours Friday 13th!

[RitchieTheBrit]

Re: G&P M4 possible piston/gear issue?

Check the teeth on your piston, probably caused some damage, if so it's a check fix.

[Reaperman]

Re: G&P M4 possible piston/gear issue?

Knackers, will do. Any particularly decent strip down vids you'd recommend? I'm good down to the piston and motor area really, haven't dabbled there yet....

Also, check fix? Do you mean quick fix on a typo?

[jonny lovegrove]

Re: G&P M4 possible piston/gear issue?

I think that's what he meant. Tbh there are quite a few videos on the tube, just find one without a nasal American doing the commentary. It's quite a simple process after the first time

[RitchieTheBrit]

Re: G&P M4 possible piston/gear issue?

Ha! Yeah, thanks for the duff auto mis-correct, HTC!

[RitchieTheBrit]

Re: G&P M4 possible piston/gear issue?

Pretty good video...
https://youtu.be/FWPEoVyiEXc

[Reaperman]

Re: G&P M4 possible piston/gear issue?

Pretty good video...
https://youtu.be/FWPEoVyiEXc

Cheers, Reckon I'll stick to just down to gearbox level at the min, opening that up looks like sorcery to me.... might get a project gun to work on or something rather than the inevitable trashing of my lovely gun

[RitchieTheBrit]

Re: G&P M4 possible piston/gear issue?

It's HONESTLY easier than it seems.

[Reaperman]

Re: G&P M4 possible piston/gear issue?

Reckon you're right but I've found mine seems to be a particular PITA to work on to be honest (upper/lower receiver pin an unbelievably fiddly 3 piece design, rear tube screw and plate is the devil's own job to align and get back on etc) so I reckon the deep internals might bake my noodle.