Cyma M14 - needs a bit of fettling

[RostokMcSpoons]

I've picked up a nice Cyma CM.032 M14 rifle from the classifieds.  It's in great nick physically but it is chrono-ing a tiny bit on the low side (315fps with 0.20's)
That's not an enormous issue, but the fact it's not wanting to hop 0.28's rather is.

So I think I need to try a new hop rubber in there... but I've looked at the disassembly videos - they look a bit .... involved.
Please give me some confidence I'm not going to bugger it up
Any recommendations for a good hop rubber (and nub)?

Also, the stock, being long and all-plastic, is a bit creaky at the front end... are there any easy fixes for that?

 

[Impulse]

Take your time and leave everything in deliberate locations. When I did my first work on my m14, it took me three hours to take it apart, sort all the gearbox items and then put it all back together. It's not difficult, it's just long and needs a bit of getting used to. The good news is you don't need to take everything apart to get to the barrel and hop rubber; yes, it's still more involved than an m4, but getting to the barrel and hop up isn't difficult as all you do is remove the trigger guard, separate stock from receiver, remove bolt return spring, undo 6 screws around where the outer barrel meets the receiver and separate the two. You don't need to get tied up with all the springy bits on the side of the gearbox  

In terms of hop up rubber, I use a Maple Leaf 60 degree macaron in mine with an omega nub and it's really, really good. You'll need to trim down the hop up rubber a little because m14s are weird and use shorter rubbers that nobody makes by default, but that's easy to do and it doesn't have to be absolutely perfect.

In terms of the stock, it's not amazing quality and mine is creaky too, however it hasn't given me any issues so it appears to be fine. My TM m14's stock was way nicer, but I guess that's what you get for paying over double the price  

For a full disassembly and reassembly, I use this video and just follow along if I ever have to get into the gearbox. It's detailed in all the right places.

 

[RostokMcSpoons]

Ordered the rubber and nub... and also ordered a scope mount off AliExpress so I can go for the Black Hawk Down look.

View attachment 93622

There aren't of these darned things anywhere I could find in the UK, so it'll probably take weeks to arrive... but it'll be cool.  (But this gun is going to be HEAVY when it's got a sight on it too)
 

Is it worth getting a ZCI inner barrel too?

 

[Impulse]

Is it worth getting a ZCI inner barrel too?

I would say so. £25 isn't a huge investment for a stainless steel barrel

 

[Lozart]

Is it worth getting a ZCI inner barrel too?

Absolutely. That and a Maple Leaf rubber and nub and a patient and methodical approach to stripping it down.

I've put a Rocket 28TPA motor in ome of mine and that has improve the RoF quite nicely too.

 

[RostokMcSpoons]

I've put a Rocket 28TPA motor in one of mine and that has improve the RoF quite nicely too.

Yeah it could definitely do with some improvement... Is that a straight swap or did you have to re-shim the gearbox?   Does it need an 11.1v battery to drive it properly?

I really don't want to open the gearbox, my tech'ing skills don't appear to be up to the job

Oh, and I take it the inner barrel is 550mm? @ak2m4 - any idea when you'll have more stock?

 

[Lozart]

Yeah it could definitely do with some improvement... Is that a straight swap or did you have to re-shim the gearbox?   Does it need an 11.1v battery to drive it properly?

I really don't want to open the gearbox, my tech'ing skills don't appear to be up to the job

Oh, and I take it the inner barrel is 550mm?

I haven't shimmed the box....yet. The pinion on the rocket motor doesn't quite mesh right but much like you I'm not really looking forward to opening it up just yet. I'm running mine on a 7.4 but I am planning to go Warfet or Perun with it at some point.

The TM style V7 box is just a very lazy running setup as is. There's definitely ways and means to make it snappy AF (see Negative Airsofts M14 video for proof).

 

[RostokMcSpoons]

much like you I'm not really looking forward to opening it up just yet

I thought as I picked this one up for a very reasonable price I might use the 'saving' to have a professional fettle it for me... so Cage Airsoft sprung to mind... do they have a good rep?

 

[Lozart]

I thought as I picked this one up for a very reasonable price I might use the 'saving' to have a professional fettle it for me... so Cage Airsoft sprung to mind... do they have a good rep?

As far as I know yes, but personally I'd get it onto Luke at Negative Airsofts waiting list!

 

[Impulse]

Yeah it could definitely do with some improvement... Is that a straight swap or did you have to re-shim the gearbox?   Does it need an 11.1v battery to drive it properly?

I really don't want to open the gearbox, my tech'ing skills don't appear to be up to the job

Oh, and I take it the inner barrel is 550mm? @ak2m4 - any idea when you'll have more stock?

It's 500mm. 550mm will fit, but it'll stick into the flash hider / suppressor if you use one a little. Outside of ZCI barrels, that are cut for m14 hop units as well, most 550mm barrels wouldn't work in an m14 anyway because the hop up unit is weird.

 

[RostokMcSpoons]

As far as I know yes, but personally I'd get it onto Luke at Negative Airsofts waiting list!

Isn't his waiting list about 3 months longer than the wait for the Second Coming?

I could give it a try...

Do any of these guys discount for multiple guns?  I could send.... (counts out loud on fingers) seven guns to get fixed / fettled if I wasn't going to get absolutely ravaged on the total cost.  Shipping might be 'fun' too.
 

It's 500mm. 550mm will fit, but it'll stick into the flash hider / suppressor if you use one a little. Outside of ZCI barrels, that are cut for m14 hop units as well, most 550mm barrels wouldn't work in an m14 anyway because the hop up unit is weird.

Excellent, thanks, that saved me from a silly mistake!  Actually, is shorter an option? AK2M4 has the 494mm in stock, everything longer is out of stock.  Is a bit of tape around the end of the barrel enough to locate it properly?

(I'm just asking these potentially stupid questions so I can try to do all the hop and barrel work in one go, rather than two.  The heat is making me feel lazy)

 

[Lozart]

Isn't his waiting list about 3 months longer than the wait for the Second Coming?

I could give it a try...

Do any of these guys discount for multiple guns?  I could send.... (counts out loud on fingers) seven guns to get fixed / fettled if I wasn't going to get absolutely ravaged on the total cost.  Shipping might be 'fun' too.

I very much doubt there's a multi buy discount. It's not like buying Jaffa cakes from Tesco!

Excellent, thanks, that saved me from a silly mistake!  Actually, is shorter an option? AK2M4 has the 494mm in stock, everything longer is out of stock.  Is a bit of tape around the end of the barrel enough to locate it properly?

(I'm just asking these potentially stupid questions so I can try to do all the hop and barrel work in one go, rather than two.  The heat is making me feel lazy)

6mm isn't going to make a difference, go for it.

Also - it's not "lazy" it's "efficient use of resources".

 

[Impulse]

Excellent, thanks, that saved me from a silly mistake!  Actually, is shorter an option? AK2M4 has the 494mm in stock, everything longer is out of stock.  Is a bit of tape around the end of the barrel enough to locate it properly?

(I'm just asking these potentially stupid questions so I can try to do all the hop and barrel work in one go, rather than two.  The heat is making me feel lazy)

Usually shorter is only an option at 420mm, because most barrels aren't cut for m14 hop ups. However, the ZCI barrels have both regular and m14 hop unit cuts, so you could go with the 494mm and you won't have any issues. The outer barrel on the m14 hugs the inner barrel the whole way through, so I don't think you'd even have any issues with it being off-centre either.

And it's not a stupid question. Even with me google searching these issues, I ended up buying a 509mm barrel from Umbrella Armory for a pretty penny to stick in my m14 back in the day, only to realise it didn't fit. It has been sitting in my parts drawers for years and I'm only now finally digging it out for my SR-25 build  

 

[RostokMcSpoons]

Thanks Lozart, much appreciated!

Actually I read the description of the ZCI barrel, it comes with a groove + O-ring near the end of the barrel to stabilize it within the outer barrel... I don't even need to break out the electrician's tape it seems!  
However, it's £30 I don't necessarily need to spend... I might actually be less lazy / efficient and just try the hop rubber and give the barrel a good clean-out to see if that improves matters anyway... then I could spend the £30 on the new motor instead.
 

I very much doubt there's a multi buy discount. It's not like buying Jaffa cakes from Tesco!

Funnily enough I've just eaten a few jaffa cakes.   Chocolate gone melty.  Bwaaaah.   But still delicious of course

Well, it's not surprising but I had to ask.  In fact I  already fired off a quote request to Cage, to fix my F2000 (which still has a problem with the COL / trigger sledge and jams after a few shots) to test the waters, and did ask if they could do anything on the price for a bunch of guns.

 

[-davo-]

Just finished work on my own CYMA M14 (DMR)

Taking it apart is like any other gun - easier after you do it a couple times
The gearbox can definitely be a little finnicky. It has a few small springs, and free-floating parts, with little bits that will definitely want to ping off and be lost forever

Main bits I did;
- ZCI High Torque motor
- m140 spring
- Short stroke by 2 (knocked 40fps off each tooth)
- Flat hop nub
- Steel bearing spring guide (stock one is plastic)
- Perun AB++ Mosfet
- New piston/head (previous one had a bit of wear on the runner)
- Degrease/regrease, general cleaning of hop/rubber/barrel

- Shimming is tricky with m14 (see Negative's vid), it is a noisy gun, you can quieten down a little, but, it's a loud boi
I kept the shimming basic on the spur and sector, .1mm each side, and shimmed the bevel up .5mm total (.1mm on top), which gave me a happier sounding motor
It's likely possible to shim the other gears further to reduce up-n-down more, but I know the GB can be fussy, so didn't feel need to chance it

Some notes;
- Take it steady on disassemble (as you generally should)
- Hop rubber is the shortened type, like snipers, so either buy to suit or cut one down if you're confident
- The window to the gearbox is about half the opening to what you'd usually expect, so can be hard to get fingers through to hold cylinder down -- if you need to stick a stronger spring in there
I used a magnet (taken from an old speaker) and a screwdriver in the spring guide to help hold in the spring so I could put the case on

- CYMA is a TM clone, so is compatible with TM replacements/parts
- the G&G M14 is it's own thing, steer away from parts for your CYMA

Any questions/issues, feel free to shoot me a DM

 

[Lozart]

Just finished work on my own CYMA M14 (DMR)

Taking it apart is like any other gun - easier after you do it a couple times
The gearbox can definitely be a little finnicky. It has a few small springs, and free-floating parts, with little bits that will definitely want to ping off and be lost forever

Main bits I did;
- ZCI High Torque motor
- m140 spring
- Short stroke by 2 (knocked 40fps off each tooth)
- Flat hop nub
- Steel bearing spring guide (stock one is plastic)
- Perun AB++ Mosfet
- New piston/head (previous one had a bit of wear on the runner)
- Degrease/regrease, general cleaning of hop/rubber/barrel

- Shimming is tricky with m14 (see Negative's vid), it is a noisy gun, you can quieten down a little, but, it's a loud boi
I kept the shimming basic on the spur and sector, .1mm each side, and shimmed the bevel up .5mm total (.1mm on top), which gave me a happier sounding motor
It's likely possible to shim the other gears further to reduce up-n-down more, but I know the GB can be fussy, so didn't feel need to chance it

Some notes;
- Take it steady on disassemble (as you generally should)
- Hop rubber is the shortened type, like snipers, so either buy to suit or cut one down if you're confident
- The window to the gearbox is about half the opening to what you'd usually expect, so can be hard to get fingers through to hold cylinder down -- if you need to stick a stronger spring in there
I used a magnet (taken from an old speaker) and a screwdriver in the spring guide to help hold in the spring so I could put the case on

- CYMA is a TM clone, so is compatible with TM replacements/parts
- the G&G M14 is it's own thing, steer away from parts for your CYMA

Any questions/issues, feel free to shoot me a DM

Have you got precocking enabled on the Perun? I wanted to use one on my EBR but when I found out you have to pull the trigger AND push a button on the mosfet to release it, it put me off a bit.

 

[-davo-]

Perun settings I'm using so far;
Burst - 2 (almost puts full auto to single fire, odd double tap, there's no selector switch, so it's mech locked to semi, but it's just incase the cut lever somehow moves)
AB - 3
Precock - 1 (2 isn't too bad, but sounds happier with just that 1 level on)
ROF reduction - OFF, any levels in this will fuck with the semi fire shots (will cause it to half cycle essentially)
DMR mode - OFF (i will likely have this set to 4, for ~1 second delay), It's not exactly a spammable wep by any means, but any delay will stop overkill to an extent
LIPO Alarm - ON (not even using lipo, but i imagine this may work with Li-Ion and NIMH to some degree)
 

oh well look at that;
"While precocking is on, the AB setting becomes irrelevant. However, any programmed AB setting will be stored in memory and will become effective as soon as precocking is disabled."

So, can basically ignore what AB setting I have

 

[RostokMcSpoons]

I have to say I don't fancy the little parts pinging around, once I'm done with the hop and the barrel I'm leaving everything else alone so it can be a reliable back-up / occasional use gun!

 

[-davo-]

I have to say I don't fancy the little parts pinging around, once I'm done with the hop and the barrel I'm leaving everything else alone so it can be a reliable back-up / occasional use gun!

Sounds like a good plan
"If I ain't broke...." and all that

If you do decide you wanna do any internal upgrades/servicing at some point, give me a shout
Will float the offer of doing it for you, if you like, I'd be much cheaper/quicker (turnaround) than the usual go-to's, aha

 

[RostokMcSpoons]

Sounds like a good plan
"If I ain't broke...." and all that

If you do decide you wanna do any internal upgrades/servicing at some point, give me a shout
Will float the offer of doing it for you, if you like, I'd be much cheaper/quicker (turnaround) than the usual go-to's, aha

Excellent, I'll bear that in mind!