Tokyo Marui MP5K "Kurz" AEG

[sp00n]

The little MP5K that could

 

Out of the box rifle specifications:

FPS: around 230-250 with 0.2's

Barrel length: Supplied with a 110mm brass barrel.

Supplied with: 30rds Magazine, 200rds BB, Loading Rod, Cleaning Rod, Manual

Rails: Adapters needed

Hop: Yes, its there, adjustment tab is accessible when removing the front grip

Gearbox: V2, with a V3 spring guide, i also believe it is unique as it has a top sliding clip that i have never seen on v2/v3 video's on youtube (i may be wrong here)

Motor: Marui EG700 super custom

 

I originally bought this gun back in 1998 or 1999, when me and my brother were having a bb gun arms race (this gun pretty much ended it), and at £250 it wasnt cheap back then. If i said it had 5000 bb through it, back then before i lost interest and put it away. Anyway after rediscovering it, and with out any lube/mods etc (except a new 8.4v 1600 battery as the original one is MIA) i had it chrono'ed at 210fps with 0.2's which i dont think is bad at all all things been considered. (i dont know standard chrono figures but i have seen 235fps with 0.25's)

 

The standard mag is painfully small (on full auto it lasts only some 3 or 4 seconds), so i bought a 560 round hicap for an mp5, which works a treat ... i now get some 45secs at full auto lol

The loading tube is also useless (thank god for speed loaders )

 

So in preparation for Sunday night, i did a strip/clean on the gearbox (my first time ever poking around in a AEG gear box). There was either no lube on the gears or it escaped while in storage! the lube on the piston had gone a brown'ish colour ... so following a few guides i found, every part was cleaned and re-lubed with either white lithium grease (gears) or silicone grease (piston). once done and reassembled it was sounding sweet as a nut again

 

I did 1 game with it on Sunday night, and i must say i didn't like it, it needs a stock badly! and some sights, the standard iron sights are not that good or adjustable.

 

so future plans :-

stock ... probably a crane stock

RIS rails ... and a laser

Sights ... maybe a 551

Silencer or tracer

Complete tune up (to be determined)

rewire with mosfet and deans connectors

 

i dunno why but i did have quite a idea about getting the longest silencer i could, so i could fit a longer barrel which then lead to a mad idea about a mp5k DRM setup ... it would either be pure win or mega fail .... probably more fail now i think about it in the cold light of day

 

edit added original pic

[sp00n]

Revision 1

more to come

edit :- well i have got/fitted the following :-

Guarder steel original type gears
Guarder bearing set
Guarder Shim set
Guarder SP100 spring
G&P M120 HS motor

CYMA RIS kit
551 sight
Stock
Laser
front hand grip

so last evening i played a few games with it, major improvement , the holo sight was too bright though i couldnt seem to dimm it enough ... gunna try and discharge the batteries abit, she chrono'ed out at 300fps on 0.2's, which is low, and only 11.2 bb's per sec which is also low

so i stripped her again today, and i found that i had got the cylinder the wrong way round, and a shim wrong on the bevel gear , corrected it, reassembled, working brilliantly now, much quieter ..... except my hi-cap mag can not keep up , stripped/cleaned/lubed it .... its working better now, but i can only fire in bursts of 3-5 rounds

as i see it i have 2 options, either buy a load of mid caps (why dont they do box sets of 120 round med caps ) or try to get hold of a electric mag .... hmmm C-mag

Edit :- think i may have solved the issue with my hicap ​ , i completely stripped it (if you need any info on a 560rd hi cap stripping pm me), cleaned it, used a tiny bit of silicone oil on the moving bits, wiped off excess ​ , then trimmed a tiny edge off in the bb track where it goes from the winder to the feed track ..... tested and it works!! keeps up with the new rof of the gun excellently

Edit 31/5/13
So I have fitted the stock, swapped all the wiring, fitted and sorted the MOSFET.

I am having issues with my 650rd hi cap, it just won't feed more than 10 shots at a time in auto have tried stripping and cleaning it but no joy. A 200rd hi cap seems ok so dose the 100rd mid caps that I bought.

Had it chrono'd @ 17bb's per sec (was expecting 20'ish) and only 185fps with 0.25's I was a little disappointed.

So I ordered :-
New tm hop rubber
Guarder piston head
Air nozzle
Seals piston/cylinder head etc

Went to open the mech box, only to be greeted by a collapsed bearing on the spur gear
The new guarder piston heads screw doesn't screw in the head!! And checking the existing piston/cylinder/cylinder head/nozzle I can find no air leaks or reason why the fps is so low

I have fitted the new hop rubber, the old one looked ok to me barrel (standard) looks straight with no defects. I did check the nozzle to hop and I think the new nozzle looks slightly better, as the original one instead of a round hole had a cross one which seems odd

So there I have it a box of mp5k till I get some new bushings (decided not to go with bearings again as I have read that 6mm bearings are prone to collapsing)

Edit 6/6/13

So today I received my new g&g oilite bushes, and a asg ultimate cylinder, and so began the reassembly.
First issue was the bushings were tight on the gears, I had to work them to get them to fit, it's not a major problem though as they will bed in, and I gave them a good lube

Next issue was the bearing that had collapsed, had been eating away at its housing, and the bush is a little slack in there and can rotate could mean the gear box is knackered but I have a few idea's to try.

So the guarder piston head is useless, and isn't going to fit this life time with out major mods. The shs piston seal leak like a sieve so I am back with the original tm o ring, which seems ok to be honest.

The asg cylinder looks fantastic though, and the air vent is further back so fingers crossed I should get a decent fps now.

The new air nozzle looks good and seems to work well.

Finally managed to get it all back together took a few hours as I kinda lost a spring from the trigger

Now on to the testing my g&g cm16 raider is some 330 - 350 fps, testing on a can it can punch straight through it with 0.25's my mp5k can only just punch through one side I am at a loss as to why the only thing I can think off is the hop to nozzle distance or maybe the barrel length.

For now I am gunna finish reassembling it, let everything bed in but I am a little disappointed as I thought the fps would be much better.

[sp00n]

Well today I received and fitted the new ASG ultimate cylinder head and piston head. Think I may be narrowing in on the air leak(s)! As tests on a can have shown it can now penetrate a can with ease!!!

A major result I am now looking at a deep fire nozzle and trying some other idea's

 

took the gun apart again, to do the "Teflon tape round the bucking" trick, when i happened to put the mech box and hop units together, and noticed that i could see the end of the air nozel in the hop! further investigation revealed that there appears to be a 3mm gap between the bucking and the air nozzle .... all i can think of is this is how there meant to be ... yet from all my research i have read that the nozzle should seal on the bucking

 

This leaves me thinking that the crafty TM ppl engineered this into the gun to prevent any FPS increases ....... not to be beaten, and from my other post in the AEG help section, i have found that the nice AUG nozzle is 24.60mm, a full 3.57mm longer

 

so £7.99 later i have a Lonex aug nozzle on its way to me

 

This 3mm gap may also explane why the 650rd hi cap dosn't seem to work very well, as the air leak could be pushing the bb's back down into the mag

 

new nozzle and more testing to be done!

 

Edit 23/6/13 :-

seems the nozzle wasnt the problem! there was a small ball bearing out of the bearing that went pop stopping the tappet plate fully going home!

 

all cleaned out again, and i fitted a ultimate aluminium piston head ... which is nice, although a few days later the gear box locked up ... it seems the piston head had been winding its self off!

 

so using the screw off the ultimate piston head i mannaged to get the guarder piston head to fit ... although i did find out that the original piston final tooth (metal) was slowly bending into the piston, and reducing its contact area (well it is 13+years old) ... anyone else get the feeling that this is going from bad to worse!!

 

ok so future plans are either ...

 

1)get 8mm gearbox (ultimate do a nice one)

2)get full metal tooth piston

3)super high speed gears

4) better motor (as i noticed some wear on the bevel gear on the motor, yet the height is set correctly )

5)replace other bits that are showing signs of age/wear

 

Or ...

 

1)kill it with fire

 

oooh and the 560 high cap still dosnt work in auto, semi ok, yet a 200rd high cap works fine, so unless the spring is shot in the 560 i have no idea whats wrong with it.

 

edit 3/7/13

 

so the 560rd hi cap is pants, i have had it apart and swapped the main spring for a m4 hi cap spring .... still wont keep up in auto

 

i have ordered 3 200rd hi caps though as i know they work

 

as for the rest of the gun, here is my short list:-

 

i think its time to ditch the 6mm gear box and get a proper 8mm gearbox

go down the hose route, 13:1 gears

get a better motor (high torque ... maybe)

get a metal tooth's piston

get a M120 spring (as i am only getting 240'ish fps with a m100)

new springs and tappet plates etc.

 

but all that lot will have to be next month or later

[sp00n]

minor update :-

 

so i got hold of a few 200 rd hi caps but they too had feed issues, i would fire say 10 round then miss a few, then 10 more, like the mags couldn't keep up

 

this issue has been sorted by the fact that i have finally got me a full electric sound activated C-Mag (technically is called a S-mag), with 2500 rds of goodness but its not all joy and happiness its a bugger to refill, you literary need 3 hands to do it! one to hold the drum flap open, one to hold the mag, one to pour bb's in, even then you maybe get 100 rds in before you have to shake them round the drum

 

so i have managed to get a SHS full metal tooth piston (i know a lot of people say you shouldn't on a speed setup, but its my gun ) ready, and i have been looking at gear boxes. Atm i am just running with my gun how it is, it works quite well but i am all too aware that at some point something is going to give