My MP5

[DanBow]

No real reason for this post, other than to show off my CYMA Blue MP5.

 

Im a very, very happy boy. 🥰

[The_Lord_Poncho]

Lovely blaster! I bought the same a year or so back, and its been a solid performer completely stock. I keep meaning to swap the hop rubber to see if that increases the range a tad - that's the only area I feel its a bit lacking compared with my other rif's. I enjoy how solid/heavy it is for such a little compact package.

[DanBow]

23 minutes ago, The_Lord_Poncho said:

Lovely blaster! I bought the same a year or so back, and its been a solid performer completely stock. I keep meaning to swap the hop rubber to see if that increases the range a tad - that's the only area I feel its a bit lacking compared with my other rif's. I enjoy how solid/heavy it is for such a little compact package.

 

Ive played a few times but im still a newbie so while i was at the site yesterday i got the owner to have a look. He set the hop so that its almost laser like out to about 30m ish. That's on .25s though, he says it'll be better on .28s so there some on the way. 😁

Other than that, it'll stay stock.  At least until i know what im doing! Lol

[Sewdhull]

I got the sd6 version, nice gun. Had to fettle the selector tho.

[DanBow]

5 minutes ago, Sewdhull said:

I got the sd6 version, nice gun. Had to fettle the selector tho.

 

Yes, the selector is a little  . . . something, i can't think of the right word, but I've jus put that down to it being virtually new. What fettling did you do?

[CrackCommandoUnit1972]

You cant beat a MP5.

[RostokMcSpoons]

25 minutes ago, CrackCommandoUnit1972 said:

You cant beat a MP5.

 

 

But you can beat an egg

 

 

I'm not sure where I'm going with this....

[gavinkempsell]

11 hours ago, Sewdhull said:

I got the sd6 version, nice gun. Had to fettle the selector tho.

I've never been keen on MP5 selectors, kind of turn & twist at the same time IMO.

[The_Lord_Poncho]

You've gone and inspired me to dig mine out ready for some CQB action tonight at Invicta Black Site! I have been thinking of swapping the motor our for a high torque, but after a few dry shots earlier on a 7.4, to be honest I'm happy with its snappiness.

 

Always a pain to rig a light and pressure pad onto it with a classic hand guard though. Good job that cocking handle isn't needed

 

 

[Sewdhull]

On 05/12/2023 at 10:43, DanBow said:

 

Yes, the selector is a little  . . . something, i can't think of the right word, but I've jus put that down to it being virtually new. What fettling did you do?

First thing was pull the lever out, there's a grub screw on the left to undo and then pull the lever out.

There's another grub screw holding the lever to the shaft and this was sticking out too far and interfering with the body. Had to file it flush. It's locktighted in so I couldn't remove it.

This helped but I had more.

 

I made the mistake of looking at some of these falling down an internet rabbit hole and ended up hanging my nose over the gun in the title.
 

     
 

    Of course I then bought one and following are my thoughts on the gun.
 

     
 

    In case you don't know what it looks like... https://images.app.goo.gl/9mtVnfitABNswYUX6
 

     
 

    For me it's a sexy gun, maybe the sexiest. Sexy and heavy. It weighs 3.6kg with mag, battery and sight and more than a little front heavy.
 

     
 

    It's the Blue version, so inside it should have half decent bits and clearly the air seal is ok, firing at  365 fps on a .2g BB, through its little 220mm barrel. It's happy on a 3S lipo or a 3S life.
 

     
 

    I swore to myself I would use it before taking it apart, but I didn't. It had a very clunky fire selector which bothered me greatly so I pulled off the sliding stock, which is very nice and sturdy, with a great extending action (only 1 of the 3 extended positions is useful to me, so I will mod those later)
 

    Once the body pin was out, I slid out the gearbox out and pondered the fire selector.
 

     
 

    I am used to a G36, they are V3 gearboxes and this is a V2. I don't recall working on a V2 before so of course I ploughed ahead, pulling the motor out and sliding the plastic bits off after taking the fire selector levers off ( grubscrew on the left, then pull the shaft and right selector lever through the gearbox.
 

    There's a "plastic bit" that sits in the plastic lower, through which the selector shaft passes from the right and gets sandwiched by the right selector lever. 
 

     
 

    Anyhoo, the gearbox has a quick change spring, a shiny ribbed cylinder and a plastic nozzle, sans o ring. The casting is textured for some reason, it's not radiused and not shimmed properly.
 

     
 

    I noted that the plastic fire selector plate was binding leaving safe to semi on the contacts, which stuck up really high, so the copper part of the fire selector plate had a lot of work to do to get past them. I imagine it's meant to electrically disconnect the  trigger as well as mechanically lock the trigger on safe, but it doesn't do the electrical isolation. I will probably rewire this given the pointless contacts.
 

    The fire selector plate and the aforementioned "plastic bit" ( a sort of cam) work together provide a crude detent, in addition to the detent in the left fire selector lever, when selecting safe, semi and auto. For safe the plastic bit has kind of beak that goes over centre on the bottom of the fire selector plate, on semi there's a nub on the plastic bit that nestles against a raised bit on the fire selector plate and on auto, the aforementioned beak engages the raised bit.
 

     
 

    To smooth all this out required:
 

     
 

    Pushing the contacts down ( they may have been incorrectly seated) so the fire selector plate would move more freely
 

    Taper the beak of the plastic bit, so it would engage safe with less force and move from safe to semi with less force.
 

    Reduce the size of the nub on the plastic bit to engage semi from safe more smoothly.
 

    Taper the top side of the beak so it would more easily engage in the auto position.
 

     
 

    There is still a detent effect putting the fire selector plate in the right place, which now works with the fire selector levers own detect, meaning it all clicks into place now. Much like my G36s.
 

     
 

    Having, as previously mentioned, sworn to not take this thing apart I now have a list of things to do.
 

     
 

    Spring change, maybe nozzle change.
 

    Shimming and consequently adjusting motor height.
 

    Filling in the 2 useless cut outs in the sliding stock so it slides to the right position.
 

    Add a MOSFET ( nothing fancy, I have a load of 3034 chips to use) Some of the MOSFETs used in the posh ETUs are really not very good. Altho the Jefftron ones are very nice.
 

    Rewire the thing in decent cable (the PVC stuff doesn't like the bends this gun seems to require and it uses  lot of it, going to the back of the gun from the gearbox then to the front to the battery)
 

    Short out those weird contacts under the selector plate and get the copper off it.
 

     
 

    That's probably enough for now, please feel free to tell me where I'm going wrong or what else I might do since I am already doing this ^^^
 

     
 

    Maybe you've noticed there are not many pics, Some tech issues prevented them appearing here. I'll add them as soon as I can.
 

     
 

     
 

                                  
 

     
 

     
 
https://airsoft-forums.uk/topic/57368-cyma-mp5-sd6-thoughts/?do=findComment&comment=493052

 

 

Edited December 6, 2023 by Sewdhull

[DanBow]

@Sewdhull

 

Even as a newbie, i sat in bed (still recovering with a broken leg) and stripped it down as far as I dared. I got it down to gearbox out but went no further. I thought maybe polishing the metal under the selector switch might help but after reading tour comment realise there's going to be more to it. More than im comfortable with doing at the moment.

 

I like what you're going to with the retractable stick though. What are you going to use to fill the voids?

[Sewdhull]

On 05/12/2023 at 10:43, DanBow said:

 

 

Filing the grub screw down doesn't need any disassembly other than that shaft. My grub screw was rubbing plastic from the handgrip plastic. You do need to take the plastic grip off to do the rest. Gearbox is untouched.

The slots can be filled with JB weld etc as the locking tabs are plastic.

I haven't done it yet tho. I'll take the part down to metal and put tape on it to make a mould to put the epoxy in.

I have a full stock which I might use instead since the collapsible stock has limited utility.

 

[Lozart]

18 hours ago, gavinkempsell said:

I've never been keen on MP5 selectors, kind of turn & twist at the same time IMO.

 

That's why I've gone with an SEF lower on all mine. The right side of the ambi selector always digs into my trigger finger.

[Sewdhull]

Where did you find the SEF receiver?  I can't recall seeing one and I mooched around MP5s for ages before buying one.

[Lozart]

15 hours ago, Sewdhull said:

Where did you find the SEF receiver?  I can't recall seeing one and I mooched around MP5s for ages before buying one.

 

My MP5s are Classic Army for the exact reason that I wanted SEF lowers. There's a few available as parts, I think ICS still do one.