G&P M16 Fifth Piston in a year

[Mac4456]

Right guy and gals, ive had my G&P M16 for just over a year now and its stripped 5 pistons? for 2 of them ive been running and 9.6v battery but the other 3 go within about 200 rounds on a 8.4v? Any ideas what it could be? and ive had it repaired by professionals each time and they just keep replacing it?

Thanks
Mac

[big smudge]

Re: G&P M16 Fifth Piston in a year

i would look at changing the spring for a less powerful 1 and maybe the motor too, try to resort back to a basic Gear box layout to see what happens then

[starscream]

What brand pistons were you sing out of interest? Might be worth investing in one with metal teeth.

[Mac4456]

Re: G&P M16 Fifth Piston in a year

I havent changed anything in the gearbox from factory, the G&P M120 is standard with these
M16's so on theory shouldnt need replacing. And Ive tried Madbull pistons with metal teeth, and 2 G&P and JG and a systema one i think. Any other ideas guys. Thanks for the advice so far

[Crude Skinny B]

Re: G&P M16 Fifth Piston in a year

Get an shs piston the blue one and correct the angle of engagement

[johnnyj]

Re: G&P M16 Fifth Piston in a year

I work on 2-3 g&p's per week for different sites and it is very rare for me to replace a piston
sorry to say are your techs making sure the pistons fit the gearbox? ( where are the pistons stripping ? )

[laurence]

Re: G&P M16 Fifth Piston in a year

Are you sure your AOE is okay? because i cant really think of anything else it could be...

[Mac4456]

Re: G&P M16 Fifth Piston in a year

well i assume the AOE is okay as its been done by a company and there are all stripping at the back and wearing the back 6 strips off

[laurence]

Re: G&P M16 Fifth Piston in a year

Well that sounds like pre-engagement or bad AOE, and i doubt you'd be getting pre-engagement at that rof so im just assuming the AOE has been badly done. WHat spring you got in it atm?

[BioSniper]

Re: G&P M16 Fifth Piston in a year

^ This.
AOE is the usual culprit for the back teeth tearing off, as well as having a too weak spring with a high ROF.
So for example, a 30RPS gun with an M90 will suffer pre-engagement, possibly even when AOE corrected because the piston cannot return fast enough in that situation. It would in that instance be better to use a larger spring (M100 up to M120 in the UK) and take teeth off the sector gear.

Very large spring and very quick taps of Semi-Auto will also cause you to tear the back teeth off, especially if the AOE isn't correct. I would be sceptical that the AOE is correct unless the shop/tech you took it to specifically says they will do AOE correction considering the problems you have had.
Been servicing a mates SR-25 where this has been the issue. The high torque motor makes for excellent spring pulling but the AOE was a million miles off so the back tooth on a JG full metal rack tore itself off.