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Asomodai

'Specna' Arms M16a3/M203 Project (Update -07/04/2020)

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Hello gents. 

 

A little while ago, I picked up a second hand Specna Arms M16/M203. It was advertised as having a Madbull Barrel and Hop unit and High Speed motor. 

 

Got it in and it was firing roughly 365 fps and really struggled to pull anything on a 7.4v lipo. 

 

I removed the knackered Lonex High speed motor and installed a new GP 22TPA Neo. Much better trigger response and 7.4v lipo works fine with it. 

 

I forgot about until recently, working from home means I tough i would use the E&C system and install a new spring. Having never taken apart any part of a standard M16/M4 I knew it would be interesting. Also had a Mosfet to go into it. 

 

Well, I couldn't FIND the E&C system... this is what greeted me. 

 

1484560112_WhatsAppImage2020-03-17at11_46_57.thumb.jpeg.743707f3a222c139a3f1f9e8d06328f2.jpeg

 

Yup, that's right folks. Whoever teched this replaced the Specna internals with all G&G ones. So no easy spring change, the Hop unit and barrel was G&G stock, chewed up air nozzle and a janky ass flat hop with a guarder clear. 

 

Pretty annoyed as I have never worked on a V2 gearbox before. Now going to put together a parts list to replace most of it. Far too late to get any money back from this. Luckily the G&G gearbox shell itself is pretty good. 

 

So what shall I do?

 

Get a new Specna or improved GB shell?

 

New airseal components? Gears etc?

 

I am definitely getting a new ZCI barrel and maybe a rotary hop unit. 

 

Looks like @ak2m4 will be getting more of my custom...

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1 hour ago, Asomodai said:

 

Yup, that's right folks. Whoever teched this replaced the Specna internals with all G&G ones. So no easy spring change, the Hop unit and barrel was G&G stock, chewed up air nozzle and a janky ass flat hop with a guarder clear. 

 

Pretty annoyed as I have never worked on a V2 gearbox before. Now going to put together a parts list to replace most of it. Far too late to get any money back from this. Luckily the G&G gearbox shell itself is pretty good. 

 

So what shall I do?

 

Get a new Specna or improved GB shell?

 

New airseal components? Gears etc?

 

I am definitely getting a new ZCI barrel and maybe a rotary hop unit. 

 

Looks like @ak2m4 will be getting more of my custom...

 

So with the gearbox shell; unless it's cracked, it will probably be fine for your purposes. M16 is a metre long rifle so I imagine you wont be taking this to CQB, i.e get it dialed in for 350 and leave it - no QD spring really needed. G&G shells are pretty good - they are not your cheap ACM pot metal.

 

Once you get inside the V2 you will want to check out the condition of the piston teeth. But unless there are serious air seal issues it may be good to go regarding piston and cylinder heads - sounds like you need a new nozzle so maybe a nice metal one with an oring seal.

 

Make sure semi is functioning perfectly and inspect the cut off lever while you are in there.

 

Check the shimming.

 

clean and then lube it up.

 

One thought; you have it setup as an M16A3 - Semi/Auto. If you wanted to you could treat it as an A4 and put a burst switch/mosfet/chip inside... plenty of room in the stock of an M16, maybe a Warfet?

Obviously that's down to your own preference. I've had a lot of fun when my burst A2 has been working!

 

Obviously good shout with a new barrel/rotary hop/rubber. As always I would go maple leaf for the rubber and nub.

 

Either way, enjoy mate... full length M16s are awesome and manly! 😁

 

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how far do you want to go with this?

 

by the sounds it looks like at least the nozzle is going to need changed. personally i like the brass type with a sealing o-ring rather than plastic/aluminium.

 

you can do a few tweaks to improve the air seal, of course if you want to spend then certainly replacing the cylinder head/cylinder/piston head won't be too bad.

 

if the gears are in good nick and you don't want to do any stupid rof shenanigans then probably just leave them as-is, piston as well if it's in good condition.

 

quick change springs do make working on the box an awful lot easier, and as a quality of life thing i would say it's worth it, although there's nothing fundamentally wrong with just running the g&g shell as is, it's not like getting the box out enough to swap the spring isn't already a pain in the ass.

 

hop wise i've been really impressed with the MAXX units, dunno how well they fit specna's (i'm running an e&c reciever with a fusion engine) but the performance is amazing, a maple leaf macaron with the included R-nub and on a zci she's doing sterling work (although granted i do plan on swapping the barrel before long because muh pdi)

 

 

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4 hours ago, mzjango said:

 

So with the gearbox shell; unless it's cracked, it will probably be fine for your purposes. M16 is a metre long rifle so I imagine you wont be taking this to CQB, i.e get it dialed in for 350 and leave it - no QD spring really needed. G&G shells are pretty good - they are not your cheap ACM pot metal.

 

Once you get inside the V2 you will want to check out the condition of the piston teeth. But unless there are serious air seal issues it may be good to go regarding piston and cylinder heads - sounds like you need a new nozzle so maybe a nice metal one with an oring seal.

 

Make sure semi is functioning perfectly and inspect the cut off lever while you are in there.

 

Check the shimming.

 

clean and then lube it up.

 

One thought; you have it setup as an M16A3 - Semi/Auto. If you wanted to you could treat it as an A4 and put a burst switch/mosfet/chip inside... plenty of room in the stock of an M16, maybe a Warfet?

Obviously that's down to your own preference. I've had a lot of fun when my burst A2 has been working!

 

Obviously good shout with a new barrel/rotary hop/rubber. As always I would go maple leaf for the rubber and nub.

 

Either way, enjoy mate... full length M16s are awesome and manly! 😁

 

 

2 hours ago, Adolf Hamster said:

how far do you want to go with this?

 

by the sounds it looks like at least the nozzle is going to need changed. personally i like the brass type with a sealing o-ring rather than plastic/aluminium.

 

you can do a few tweaks to improve the air seal, of course if you want to spend then certainly replacing the cylinder head/cylinder/piston head won't be too bad.

 

if the gears are in good nick and you don't want to do any stupid rof shenanigans then probably just leave them as-is, piston as well if it's in good condition.

 

quick change springs do make working on the box an awful lot easier, and as a quality of life thing i would say it's worth it, although there's nothing fundamentally wrong with just running the g&g shell as is, it's not like getting the box out enough to swap the spring isn't already a pain in the ass.

 

hop wise i've been really impressed with the MAXX units, dunno how well they fit specna's (i'm running an e&c reciever with a fusion engine) but the performance is amazing, a maple leaf macaron with the included R-nub and on a zci she's doing sterling work (although granted i do plan on swapping the barrel before long because muh pdi)

 

 

 

 

Cheers for the response gents. 

 

Not looking to spend that much, so probably wont be going for super fancy hop units like the Maxx, I am sure something like a metal SHS or ZCI will be fine, though I am not sure exactly which one I should go for.

 

I will likely go for a Brass or Aluminium type nozzle. Something like an SHS. 

 

I was thinking of a QD gearbox mostly because I really think they make things so much easier testing after a new build, adjusting springs etc to compensate for too much FPS or overspin etc. But I can probably stick with the G&G box as I hear they are pretty good. AK2M4 have Specna QD Gearbox shells with bushings and Spring guide for quite cheap though if I wanted. Semi and shimming seem absolutely fine and RPS is perfectly fine with the High torque neo motor I have in their now. 

 

I can probably get away with the current Air Seal components as is, but I might as well replace while the box is open. 

 

Just a basic mosfet, I have a PERUN one ready to go in. Maple Leaf Macaron is already in their with a 0hm nub. 

 

I reckon it will be firing hot with my usual M95 spring, good air seal and a ZCI 509mm inner barrel. Will there be any stability problems if I go for a shorter barrel, say around 400mm?

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The early SA guns might have had QC spring boxes

but the early ones did not have this feature built into receivers

ergo you still had to remove the friggin' gearbox

which meant grip & motor, to remove the gearbox so you could "quickly" change the spring

 

Which I found kinda funny if not stupid as you got the fucking thing out so about 80% of the work

(just half a dozen screws to open the box CAREFULLY without all jumping out)

 

Later guns were properly thought out with QC receivers so you could change spring in situ

YES - to change just the spring the QC in situ is a godsend, yet unless you have the QC receiver it is not end of the world

 

In other words, unless you got the full QC receiver - then I wouldn't worry too much about a QC gearbox/shell

 

G&G gearbox - very SHS/RA compatible, SHS blue pistons don't bind like other boxes slightly bind

Not reinforced at back so 13:1's go straight in, the only qwirky thing is screws on other side/underneath

 

Not ultra strong gearboxes, but not Dairylea either - the really G&G cracking gearbox shells were the blowback's

Yours seem to be regular G&G non blowback box, so check closely up front where it is already radius'd for you

If Bronzey bushings used then deffo replace the one under spur as it is going to wear rather quickly than all others

 

The only thing I might change apart from whole piston - head I never got great compression from myself

apart from usual stuff like piston, nozzle, gears, - well basically everything that we replace I guess

Change the AR Latch to say a thinner JG type than the chunky G&G ARL

I had one break on me, it is weird the ARL on G&G's

They make a chunky looking latch with nicks in it ???

These nicks cracked on a Combat Machine I started to push & the actual arm broke clean off from shaft of ARL

(bit like a shell cracking after a manufacturer decided to start it off with little cuts already

Probably a one off manufacturing flaw/batch or just general bad luck most likely

But there is also another reason I replace G&G ARL's

They place the position of the ARL hole very close to the wiring channel and if using thicker wires

then 2.8~3mm silicone 16awg wiring or wotnot is close or does rub/impedes against the G&G ARL operating

 

pic doesn't really show you just how chunky or the "nicks"...

 

 

G&G anti reversal latch for gc - Gear Of War

 

 

Now a cheapo say JG are a bit better & less likely to rub against wiring behind the ARL...

 

Image result for jing gong anti reversal latch

 

It is the "shoulder" and the very back of ARL that just comes a bit close to touching the wires at back

and G&G have deffo placed the mounting hole a whisker too close to the wiring channel than other V2 boxes

Not a massive amount, but enough to rub on thicker wiring, that needs checking more than other boxes

plus the nicks on the ultra chunky G&G ARL can promote the G&G cracking on snappy builds

 

Now some will say they are still on their original G&G latch no problem

or it never rubs - well it won't if thin stock wiring or is front wired - duuuhhhhh

but I've only one ARL break on me and it was the G&G one so just saying or mentioning what to look/consider

 

Apart from that the G&G boxes are not that bad & like I said if you haven't got the QC receiver

then a SA QC box is not a must have as you might still have to nigh on gut the gun to change the spring

As some early SA's were not quite the QC spring like they are now

not so much QC more like MBC - Mildly Brisk Change spring, but certainly not Quick Change as such

 

You got a bit of a franky M4, from a kiddy/muppet tech who never declared it all in description

or pleaded ignorant if you moan about it - oh I bought the gun from awesome techy m8

(kid who sits next to him in class)

 

it happens, teching a s/hand gun is like trying to figure out where all the wires go on a s/hand car cd/radio player

WTF has some fucking idiot done to this, turn on radio & rear wash wiper goes nutz - yeah real joy sorting this out

 

Yours - as long as box is not cracked or threads all fucked is not quite the end of the world

any bits you replace: SHS/RA will fit in there nicely with no real issues, just the ARL is something I'd consider changing

 

any probs gis a shout

 

PS - G&G stock pistons on cheapo CM's use a small 5mm piston spacer inside piston (by default)

not quite the heavy chunky 8~9mm alloy spacer used in many China guns

but a 5mm spacer, 4mm plastic ring, with a steel washer topping it off

then a usual collar sleeve & normal M3 bolt into crappy G&G piston head

similar to the spacing a bearing piston has of top race, bearing, bottom race/washer

except not bearing/swivel dooberry

Now this might or might not still be in there, could remove it to lower fps

or take off one tooth sticking with current spring that you know what you are shooting atm

or buy a spring that isn't too hot

or use std non bearing spring guide or correct AoE blah x 3

(well you know these effect fps by +/- 15fps already)

just saying you don't have to risk playing the possible spring lottery if just shooting a smidge over 

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My gearbox parts have come in so decided to give it a go! 

 

Opened up the gearbox and this is what awaited me. Again, the internals being a surprise. 

 

dJsSlIv.jpg

 

The gearbox has clearly been worked on. The Gears are 13:1 SHS, Aftermarket piston with 13 1/2 teeth, stock brass cylinder, Lonex POM piston head and Lonex Aluminium Cylinder head. Basic metal spring guide. Slightly worn anti reversal latch but good otherwise. Standard wiring. So the original build had a High Speed G&P Ferrite motor, paired with a 13:1 gearset, no wonder it only turned on a 11.1v lipo. But had no mosfet installed! AOE is correct.

 

The Spring is quite a strong one. 

 

GUsMUtS.jpg

The air seal components are really good so will be keeping them, very good seal. 

 

mkiMgtx.jpg

 

Slightly worn piston.

 

2DMywI3.jpg

 

The original black POM nozzle looks like it had been shaved down slightly as it's shorter then my replacement. Air seal is good with the Cylinder head so I am unsure whether to replace with the new one or not. 

 

It could have been shortened because of a feeding problem. What do you guys thing I should do?

 

B5SdHzf.jpg

 

Shaved down the 13th Tooth on the new piston as the Sector was hitting it. 

 

zSiMpBM.jpg 

 

Project has stopped here, having never broken into a V2 box I was surprised how little space I had for wiring. Pictured is the thinnest wire I had which is too thick to add an additional wire for the mosfet. So have had to order some 22AWG. Until that comes through I'll have to sit tight! 

On 17/03/2020 at 18:11, Sitting Duck said:

 

Change the AR Latch to say a thinner JG type than the chunky G&G ARL

I had one break on me, it is weird the ARL on G&G's

They make a chunky looking latch with nicks in it ???

These nicks cracked on a Combat Machine I started to push & the actual arm broke clean off from shaft of ARL

(bit like a shell cracking after a manufacturer decided to start it off with little cuts already

Probably a one off manufacturing flaw/batch or just general bad luck most likely

But there is also another reason I replace G&G ARL's

They place the position of the ARL hole very close to the wiring channel and if using thicker wires

then 2.8~3mm silicone 16awg wiring or wotnot is close or does rub/impedes against the G&G ARL operating

 

pic doesn't really show you just how chunky or the "nicks"...

 

Image result for G&G anti reversal latch

 

Now a cheapo say JG are a bit better & less likely to rub against wiring behind the ARL...

 

Image result for jing gong anti reversal latch

 

It is the "shoulder" and the very back of ARL that just comes a bit close to touching the wires at back

and G&G have deffo placed the mounting hole a whisker too close to the wiring channel than other V2 boxes

Not a massive amount, but enough to rub on thicker wiring, that needs checking more than other boxes

plus the nicks on the ultra chunky G&G ARL can promote the G&G cracking on snappy builds

 

 

 

Yours - as long as box is not cracked or threads all fucked is not quite the end of the world

any bits you replace: SHS/RA will fit in there nicely with no real issues, just the ARL is something I'd consider changing

 

 

 

Heres a photo of the AR Latch. Think thats the G&G one? 

 

If1XCev.jpg

 

K4yJK5f.jpg

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looks like there's a bit too much sorbo been used for the AOE there, would explain why the sector was hitting it.

 

is there a thrust bearing inside the piston? personally i'd rather have a bearing on the spring guide and keep the piston as light as possible, especially to try and avoid PME issues for zippier builds.

 

you could give the nozzle a go, if it still feeds then the extra length is going to help it seal against the feed lips a bit better.

 

is there a tappet delay chip on the sector? might be worth investing if there isn't as that can help clear up feeding issues.

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44 minutes ago, Adolf Hamster said:

looks like there's a bit too much sorbo been used for the AOE there, would explain why the sector was hitting it.

 

is there a thrust bearing inside the piston? personally i'd rather have a bearing on the spring guide and keep the piston as light as possible, especially to try and avoid PME issues for zippier builds.

 

you could give the nozzle a go, if it still feeds then the extra length is going to help it seal against the feed lips a bit better.

 

is there a tappet delay chip on the sector? might be worth investing if there isn't as that can help clear up feeding issues.

 

It is a pretty thick Sorbo. But now the pistons been modified, might as well keep it like that. 

 

Yes there is a bearing inside the piston rather then the Spring guide. The piston I changed out for is slightly lighter then the old one which may make a difference. Before I took it apart there were no PME issues so keeping it like it is might be the better option (That and I am way over my budget!)

 

No tappet delay, but I have a spare plastic one in my box that I can use! 

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5 minutes ago, Asomodai said:

That and I am way over my budget!

 

i don't know what that word means.....

 

is it like a mechanical budgerigar?

 

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36 minutes ago, Adolf Hamster said:

 

i don't know what that word means.....

 

is it like a mechanical budgerigar?

 

 

Well. Considering I just bought a replacement AR Latch. a Hardened SHS Cutoff lever, a 16:1 gearset for the Tavor, Shims and delayer chips.. nah. 

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Not the G&G AR latch - it has been replaced thankfully

(my pic of G&G ARL was invalid so updated the original reply & here again is chunky G&G ARL with nicks)

 

G&G anti reversal latch for gc - Gear Of War

 

(the existing aftermarket ARL was perfect as is, no need to buy another for this box btw)

the box still has the G&G metal safety arm though

(nothing wrong with it - just saying the original safety is still there & is perfectly fine btw)

 

When you try to fit thicker 16awg, especially silicone 16awg the channels are tight

and the channels or gap right behind the ARL is where they can impede its operation a bit (esp on G&G ARL)

 

SHS pistons don't bind in G&G's and the reg G&G V2's have no rear window

So on the lightened SHS pistons, the boxes like G&G V2's or others is where I only would consider using them

(I'm a bit paranoid about ensuring stability on piston flying back n forth at snappy speed

others might feel I'm being a tart, but window boxes I prefer solid piston guides/runners or near enough for continuous stability at speed or under stress - just me being tarty

So the pistons with rails cut to bits I'd only use in say a G&G v2 or a v3 box myself)

 

Piston is fine, nice trim on 3rd tooth, 2nd tooth already removed (first is the pickup)

The piston will be fine I'm sure, though coz I'm paranoid about rail support I would have chosen the other lightened one...

 

image.jpeg.6be0ea5140d8fb399aea98e2f3c8315d.jpeg

but it will be fine in that non-window G&G box as I said and should not bind at all like other boxes

 

The wiring, if doing a mosfet, then just run the main motor wires down the back of pistol grip...

 

Mosfets??!! - Guns, Gear & Loadouts - Airsoft Forums UK

 

OK forget mounting the DIY mosfet in the box - NOT MY WORK btw

but shows the two wires down the back, then two thin wires to switch, in tube, glued to ensure it stays put 200%

Grind off a few of the wire tabs/pins in top of gearbox shell where the thicker wires come in & towards pistol grip

Grind the top half of gearbox at back, emulating the single wire " U " channel so that both halves take both motor wires

 

If using say silver wire or eco wire, both should pass through the single hole pistol grip at back, or very slight mod required

(thicker silicone 16awg wire needs more hacking/modding, than say silver/alpha eco wire 6716)

 

Are they SHS gears ???

Looks like the slightly cheaper ZCI/BD 13:1's at first glance with the silvery/grey sector gear

The bevel gear doesn't look SHS, does it have 4, 5 or 6 lugs ???, G&G's have 5 I think like SRC

Doesn't matter, if they roll nice, in good nick then that is all that matters

(plop a solid 8mm bushing under spur maybe, they could be G&G 8mm bearings as they didn't always use bronzey bushings

on some higher CM's they chucked in 8mm bearings like on their intermediate models - not all were soft bronzey bushings)

 

As been mentioned - consider a delayer...

https://www.ak2m4.co.uk/internal-parts/gears/zci-gear-delayer

 

install it & there is whisper thin bit of material just over the sector/tappet cam which will retract a bit more...

Gear Delayer - ELEMENT AIRSOFT

It can be a bit tight fit, you might have to file very carefully the arc part that meets the axle/spindle in center on some sectors

very little filing, a drop of epoxy might be wise to ensure it stays put perhaps

But I use these types very often as it gives a bit more tappet retraction, though you MUST check if tappet bottoms out on the cylinder head at full retraction - check in top half of gearbox with cylinder/head/tappet/ sector etc....

it can really bottom out if you use a SHS v2 tappet plate with that delayer

If so and the cylinder head can be modded slightly....

 

AIRSOFT ANODISED CNC ALLOY DOUBLE O-RING M4 VERSION 2 V2 UPGRADE ...

see that ridge below nozzle, that little rim, you can carefully file that away on some heads if tappet bottoms out

and together with delayer & SHS v2 tappet,you should attain a bit more retraction if done carefully

to produce max retraction almost, for better feeding

Sand front of tappet slightly to ensure good seal on bucking if required if slightly short/worn nozzle used

 

Depending on hop unit used, just check if the old nozzle seals on old tappet etc...

 

offer the hop unit up to gearbox with nozzle tappet at full rest

you should feel the nozzle touching the bucking lips with say 1mm to go before hop is fully rested against the box

so when all pushed home to each other, the nozzle maintains contact/resistance to ensure a seal on bucking lips

 

It might have had issues feeding like you say, then the nozzle was filed, but might have lost some seal/fps coz of it

 

Really should have used a delayer and/or SHS tappet as the aftermarket (G&G's tend to be black) tappet might have retracted less

Though as explained when using that delayer AND SHS tappet it will very likely bottom out as there is a lot more retraction

So when trying to obtain/improve nozzle travel/retraction you really need to check thoroughly in top half of box

(If done properly, it will feed well even on crappy weak spring mags - well as best as can be on shit mags, but improve feeding x 10)

 

The nozzle that is in there might be OK but might only just touch the bucking lips

I'd be tempted to sand the front of red tappet plate a bit to get the nozzle tappet to return forward a bit more

hopefully ensuring a better seal on bucking lips that "might" have been lost if nozzle was filed due to feed issues

 

I mean fuck all to lose and if goes a bit crappy then just buy a SHS tappet

You don't wanna go nutz and splash out loads of bits, but you had a touch on gears

 

Not a bad result, got some nice bits already to play with

The G&P M120 armature would go nice in a neo can

so at some point if an old neo motor croaks, pull out the knackered aramture, plop in the G&P one

should have a similar spec SHS/RA 16tpa neo motor to add some zest to a M4 or long motor build

 

If you got access to a quick change spring gun....

Test the spring in there and not the fps - even on a comparison scale than gospel fps

note the fps and/or the increase over the QC guns regular spring say 15% on fps

then decide if you might say sod it & Short Stroke the sector a couple of teeth

so that it fires at about 340fps one it is all assembled and running correctly

 

The cylinder - should have been a G&G blue steel one usually not brass

where is the port in relation to barrel length to ensure it is about correct volume ???

 

Not 101% gospel but a ROUGH guide only perhaps...

 

3iRwplA.png

 

 

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On 07/04/2020 at 17:06, Sitting Duck said:

Not the G&G AR latch - it has been replaced thankfully

(my pic of G&G ARL was invalid so updated the original reply & here again is chunky G&G ARL with nicks)

 

G&G anti reversal latch for gc - Gear Of War

 

(the existing aftermarket ARL was perfect as is, no need to buy another for this box btw)

the box still has the G&G metal safety arm though

(nothing wrong with it - just saying the original safety is still there & is perfectly fine btw)

 

When you try to fit thicker 16awg, especially silicone 16awg the channels are tight

and the channels or gap right behind the ARL is where they can impede its operation a bit (esp on G&G ARL)

 

SHS pistons don't bind in G&G's and the reg G&G V2's have no rear window

So on the lightened SHS pistons, the boxes like G&G V2's or others is where I only would consider using them

(I'm a bit paranoid about ensuring stability on piston flying back n forth at snappy speed

others might feel I'm being a tart, but window boxes I prefer solid piston guides/runners or near enough for continuous stability at speed or under stress - just me being tarty

So the pistons with rails cut to bits I'd only use in say a G&G v2 or a v3 box myself)

 

Piston is fine, nice trim on 3rd tooth, 2nd tooth already removed (first is the pickup)

The piston will be fine I'm sure, though coz I'm paranoid about rail support I would have chosen the other lightened one...

 

image.jpeg.6be0ea5140d8fb399aea98e2f3c8315d.jpeg

but it will be fine in that non-window G&G box as I said and should not bind at all like other boxes

 

The wiring, if doing a mosfet, then just run the main motor wires down the back of pistol grip...

 

Mosfets??!! - Guns, Gear & Loadouts - Airsoft Forums UK

 

OK forget mounting the DIY mosfet in the box - NOT MY WORK btw

but shows the two wires down the back, then two thin wires to switch, in tube, glued to ensure it stays put 200%

Grind off a few of the wire tabs/pins in top of gearbox shell where the thicker wires come in & towards pistol grip

Grind the top half of gearbox at back, emulating the single wire " U " channel so that both halves take both motor wires

 

If using say silver wire or eco wire, both should pass through the single hole pistol grip at back, or very slight mod required

(thicker silicone 16awg wire needs more hacking/modding, than say silver/alpha eco wire 6716)

 

Are they SHS gears ???

Looks like the slightly cheaper ZCI/BD 13:1's at first glance with the silvery/grey sector gear

The bevel gear doesn't look SHS, does it have 4, 5 or 6 lugs ???, G&G's have 5 I think like SRC

Doesn't matter, if they roll nice, in good nick then that is all that matters

(plop a solid 8mm bushing under spur maybe, they could be G&G 8mm bearings as they didn't always use bronzey bushings

on some higher CM's they chucked in 8mm bearings like on their intermediate models - not all were soft bronzey bushings)

 

As been mentioned - consider a delayer...

https://www.ak2m4.co.uk/internal-parts/gears/zci-gear-delayer

 

install it & there is whisper thin bit of material just over the sector/tappet cam which will retract a bit more...

Gear Delayer - ELEMENT AIRSOFT

It can be a bit tight fit, you might have to file very carefully the arc part that meets the axle/spindle in center on some sectors

very little filing, a drop of epoxy might be wise to ensure it stays put perhaps

But I use these types very often as it gives a bit more tappet retraction, though you MUST check if tappet bottoms out on the cylinder head at full retraction - check in top half of gearbox with cylinder/head/tappet/ sector etc....

it can really bottom out if you use a SHS v2 tappet plate with that delayer

If so and the cylinder head can be modded slightly....

 

AIRSOFT ANODISED CNC ALLOY DOUBLE O-RING M4 VERSION 2 V2 UPGRADE ...

see that ridge below nozzle, that little rim, you can carefully file that away on some heads if tappet bottoms out

and together with delayer & SHS v2 tappet,you should attain a bit more retraction if done carefully

to produce max retraction almost, for better feeding

Sand front of tappet slightly to ensure good seal on bucking if required if slightly short/worn nozzle used

 

Depending on hop unit used, just check if the old nozzle seals on old tappet etc...

 

offer the hop unit up to gearbox with nozzle tappet at full rest

you should feel the nozzle touching the bucking lips with say 1mm to go before hop is fully rested against the box

so when all pushed home to each other, the nozzle maintains contact/resistance to ensure a seal on bucking lips

 

It might have had issues feeding like you say, then the nozzle was filed, but might have lost some seal/fps coz of it

 

Really should have used a delayer and/or SHS tappet as the aftermarket (G&G's tend to be black) tappet might have retracted less

Though as explained when using that delayer AND SHS tappet it will very likely bottom out as there is a lot more retraction

So when trying to obtain/improve nozzle travel/retraction you really need to check thoroughly in top half of box

(If done properly, it will feed well even on crappy weak spring mags - well as best as can be on shit mags, but improve feeding x 10)

 

The nozzle that is in there might be OK but might only just touch the bucking lips

I'd be tempted to sand the front of red tappet plate a bit to get the nozzle tappet to return forward a bit more

hopefully ensuring a better seal on bucking lips that "might" have been lost if nozzle was filed due to feed issues

 

I mean fuck all to lose and if goes a bit crappy then just buy a SHS tappet

You don't wanna go nutz and splash out loads of bits, but you had a touch on gears

 

Not a bad result, got some nice bits already to play with

The G&P M120 armature would go nice in a neo can

so at some point if an old neo motor croaks, pull out the knackered aramture, plop in the G&P one

should have a similar spec SHS/RA 16tpa neo motor to add some zest to a M4 or long motor build

 

If you got access to a quick change spring gun....

Test the spring in there and not the fps - even on a comparison scale than gospel fps

note the fps and/or the increase over the QC guns regular spring say 15% on fps

then decide if you might say sod it & Short Stroke the sector a couple of teeth

so that it fires at about 340fps one it is all assembled and running correctly

 

The cylinder - should have been a G&G blue steel one usually not brass

where is the port in relation to barrel length to ensure it is about correct volume ???

 

Not 101% gospel but a ROUGH guide only perhaps...

 

3iRwplA.png

 

 

 

So I spent the best part of 10 hours sweet talking this blasted thing. 

 

Whoever worked on this box before stripped out so many screws in the pistol grip. It's been a nightmare. I really wish this was a Quick change spring gearbox. 

 

The gears are definitely SHS as they are branded as such. Inner barrel is 433mm long so have stuck with the full brass cylinder.

 

I used the new AR latch (Because why not). Checked shimming etc. 

 

I rewired for a mosfet, taking your advice and shoving the motor wires down the back of the pistol grip. I had to mill away at parts of the gearbox just to get the 22AWG low enough for the bevel not to eat away at them, I did try the superglue/shrink method. But ended up with plastic all over the inside of the gearbox. In the end I just have them loose and seem to be doing better. I stuck with 18AWG wire as I cant really mill out enough of the box to fit 16AWG without severe compromises. Not got the funds for silver wire at the moment either! 

 

Put the gearbox back together with a fairly light spring. It was firing at 300 FPS. Went back into the box and managed to strip some of the trigger wiring, had to redo that. Put new spring in and now up to 370 FPS! Stripped it down again and put in a spring that managed 330 FPS

 

I installed the SHS Hop unit I bought, I dremelled out the fixed plastic nub and created a new curvy bit for a nub to go in , it really struggled to feed well so put in the hop unit that came with it and changed the new arm into it. I installed a Prommy Purple and did a range test. I felt that it wasnt quite hopping .30's well enough for me, so I tried a Modify flat hop kit. The bucking was very loose around the barrel and I lost about 30 FPS and went down to 300. I struggled around with that for a bit, went back to the Prommy purple and kept the Modify flat hop nub in. Back up to 327FPS. No idea on range or accuracy as in theory a flat hop nub and standard Prommy bucking shouldn't work, but it is giving me more of a hop effect then the usual nub. Hopefully will do a range and accuracy test soon. 

 

if it doesn't work out I do have some Prommy straight bucking that I can try, but not sure the nub can put enough pressure on it. Both hop unit arms I have are pretty meh. 

 

I put about 2000 rounds through the M16 and the gearbox seems to be holding up internally. I am getting some feeding issues using High Caps, but likely just not able to feed quickly enough and causing jams. With my PTS Midcaps all is well. 

 

If I have to go into the gearbox again though I am just going to get a Quick Change gearbox and start over. The current gearbox, whilst well built is a real pain due to the tight wiring channels, stripped screw holes and the gearbox screws being on the wrong side. 

 

I'm done for the day. 

 

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Composed a bit of a War & Peace response....

but thought fuck it - said most of it ten times over etc...

 

You get to suss them V2 & V3 qwirks the more you do & all that

I spend way too long on shit trying turn a slapped together piece of Chinese shit

into something near semi precise bit of engineering which still fucking breaks at times

(and wonder why I fucking bothered at times)

 

Coz there is 1mm less tappet travel in V2's over V3's, plus floaty M4 hop units

The rather "straight forward" M4's can be easily underestimated regarding tolerances

together with wibble wobble grips/motor angles - them aftermarket clone Magpul grips are dire

(and some replacement M4 motor plates often don't fit on other M4 grips - buy a complete grip/plate)

Aftermarket grips can be complete shit (clone Magpul for starters or clone seconds G27 grips) jeeez

I've come to the conclusion stick with stock grip as it usually works OK, changing only if really needs it

(as you can run into problems/nightmares on duff ACM crap grips)

 

Whoa... going on a bit as per usual, rule #1: Change as little as possible especially on easy not so peasy M4's

I've bought a number of shit bits & learned the hard way, though if I do have to replace stuff....

well I guess I got a decent box of shit spares that something should fit and work with a bit of bodging now

 

well done for getting it back together, should be a nice M4 if you just use mid-caps & feeds OK

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