G&P M16A3 Only firing on semi - need help!

[abro1089]

First things first, absolute airsoft noob here when it comes to internals.

So, I bought this G&P M16A3 off this forum, and the guy who sold it to me says he tested it just before he sent it and it fired fine. However upon receiving the gun and putting a battery in it, the gun only fired on semi. When I switched to full auto and pulled the trigger, nothing happens. It also seems as if the trigger does not go all the way back compared to firing on semi.

What could have gone wrong in shipping to cause this?

If anyone has any ideas or advice as how to go about diagnosing/fixing this it would be much appreciated. Detailed steps may be required due to my relative lack of knowledge.

Thanks

[Sitting Duck]

Re: G&P M16A3 Only firing on semi - need help!

It is very likely a selector plate issue

The cut off lever needs to be pushed or disengaged for gun to cycle continuously

More investigation is required though as it is hard to pinpoint exact problem but quite likely selector plate related

[abro1089]

Re: G&P M16A3 Only firing on semi - need help!

Hey thanks for the reply, do you know of any in depth tutorials around that would help me go about fixing the selector plate? I wouldn't even know what a "normal" selector plate would look like haha

[Harlequin]

Re: G&P M16A3 Only firing on semi - need help!

The internet, tis a wonderful thing

https://www.youtube.com/watch?v=Wc_NBBuedRQ

- - - Updated - - -

FYI you will have aversion 2 gearbox in that beastie if you need to look up more.

[abro1089]

Re: G&P M16A3 Only firing on semi - need help!

Haha I literally just watched this video, very helpful :D

Thanks, gonna have a crack at it now

[abro1089]

Re: G&P M16A3 Only firing on semi - need help!

2015-06-05 11.52.15.jpg2015-06-05 11.52.27.jpg

Right so I've broken it down to the gearbox, and am currently looking at the selector plate. What do?

[sj_asc]

Re: G&P M16A3 Only firing on semi - need help!

If you hook the grip and motor up to the gearbox, hold the selector plate to the right so that it is lifting the cut off lever and then pull the trigger. If full auto works, that rules out the internal fault.

[abro1089]

Re: G&P M16A3 Only firing on semi - need help!

Sorry could you just run me through that again. I hook up the gearbox to the motor (while inside the pistol grip?) and move the selector plate furthest to the right then squeeze?

[colinjallen]

Re: G&P M16A3 Only firing on semi - need help!

Yes, that is correct.

[Sitting Duck]

Re: G&P M16A3 Only firing on semi - need help!

selector plate looks in pic 2 like it is busted or not much too keep it in the lower runner/guide by switch

incidently the selector plate don't have the copper strip on it - but most likely
the switch itself isn't relying on the selector plate making contact with switch contacts - bad old design and not needed
(ignore the above paragraph - just my observations)

that missing bit at bottom of selector plate by switch/safety - that ain't helping I reckon
could all be working fine though still but the selector switch in receiver could need investigating to ensure it moves the plate correctly
but by first glance looks like selector plate may have worn/chipped/broke down at bottom when it was installed perhaps
(well that is my first initial guess)
kudos for pics btw - really helps

EDIT - looks like it is snapped at top left as well so the selector was hammered in or something - ffs
looks to me like selector may have so much play up n down that moment it starts to move cut off it will just skew out out off its runner and release cut off lever - no auto

jeez who worked on this box - Stevie Wonder or Ray Charles ?????????????

Yeah reckon a new M4 selector plate required and CAREFULLY fitted
may help to unhook the spring from cut off lever with a pin or very very tiny micro screwdriver to give a smidge more room
you should be able to remove and refit new plate CAREFULLY with only a tiny little bending of new plate
re-hook spring back into place - should be sorted and working properly once more

DON'T LOSE THAT SPRING

on that box - reckon almost any old M4 selector plate should fit in there on the runners/guides nicely
(no copper contact plate on selector required - so leave or remove it ain't doing anything on that switch in your box - G&P don't use rear switch contacts)
had a JG one that had really thin narrow runners/guides and required quite thin selector plate or trim/sand a thicker plate to fit inside the selector runners/guides - whatever you wanna call them - tracks, channels or whatever ya bloomin' want
but you get the idea

[dave38x]

Re: G&P M16A3 Only firing on semi - need help!

He'll need a selector plate that accounts for 8mm bushings sticking out of the gearbox - a G&P one would be best.

The easiest way to fit a selector plate if you are feeling confident is to strip the whole gearbox!

[Sitting Duck]

Re: G&P M16A3 Only firing on semi - need help!

buying good parts is only half the story - it is how they are fitted that really counts

Never met a gearbox build yet that hasn't been improved with a little care sanding and even the odd use of a small craft file
often to remove burrs or rough edges or making parts fit better - even expensive parts

M4 & AK slector plates usually will go in ok with a bit of care without needing to strip box
G36 - they are more fragile though and need a little care or box strip if unsure

Almost any M4 plate "could" work - only way to know is suck it n see so to speak
bushings ain't sticking out that far it seems

Wonder what happened to old plate or if the one in pic is original - why did it break or why did owners remove it ??
guess we will never know complete history of box or selector plate - but see what OP can get hold of