Mp5K upgrades - why so difficult?

[jerryliang2k]

The general impression I get from reading various thread posts and articles about the MP5K is that its a huge pain in the ass to upgrade. At the same time, the MP5K mechbox is simply a version 3 mechbox which is supposed to be very accessible (motor wires aside).

So as long as I leave the motor alone, the MP5K seems like an easy gun to upgrade. Whats with all the fuss? Or am I just delusional?

Zi-Xiao

[Maverick0]

It's version 2, unless that's changed recently. Not any more difficult to upgrade than any other version 2, but then again I'm not the one doing the actual upgrading. I'm getting my mp5k upgraded hopefully this week or the next.

I've seen mine get taken apart and put back together.. maybe a little tricky without mechbox.com videos but it didn't take very long and didn't look overly complicated.

[Styrak]

Well the MP5 is a bitch to take apart, so I'm assuming the MP5k is similar. You have to take a bunch of parts off, and both sides of the MP5 body off to get to the mechbox.

[Maverick0]

Didn't look anymore difficult than taking an m4 apart. A couple pins from the body, a few screws and then it mostly slides apart. Maybe a few more wire connections to watch for than an m4, but that's it.

[DarkAngel]

Id say its simpler than an M4, because you dont have to worry about wedging in that upper onto the gearbox, then wedging the gearbox + upper into the lower (metal) or stressing the tabs to snap it over (Plastic). with the MP5 metal or plastic, you just screw it inside the upper. The hopup assemby etc would be the most complex thing on the MP5, and its not really even that complex, most of the parts are common sense. The only thing i can think of with the MP5k is when i was at TTAC3 and I think it was colin (i cant remember for sure) who was reassembling someone's MP5k and there was some difficulty stuffing the wiring back into the the short cocking tube space.

[Mysteryfish]

The MP5K is a version 3 mechbox. Doubters -> look it up. Or own one for a while...

As for the original question, it's a pain to work with the Kurz because... well...

Imagine taking a sheet of tin-foil and pressing it over something to make a shape.

The shape looks great and holds unless you try to flatten the sheet and then press the shape again.

My experience is:

The K is like that - Fresh out of the factory, it's like a freshly pressed tin-foil shape. If you take it apart and then put it back together, it seems to get "wrinkly" and doesn't "hold it's shape" as well the second time around.

[Colin_S]

LOL @ the guys above me, obviously none of you have experience upgrading MP5Ks. The K does use a version 3 mechbox.

The problem I experienced was trying to increase velocity, working on the gun is rather simple.

For me, I found the biggest thing was the length of the spring. Those long irregular pitch springs expand at the lower tension points first and push the BB out of the barrel before the higher tension parts of the spring start to expand (and transfered all energy into the BB). For instance a Guarder SP100 which usually puts out 360 fps on my G36C will only do 300 with teh MP5K

In order to get fps up with my MP5K I had to install a (I guess you call it normal pitch/spring?) phyiscally shorter PDI spring. It still suffers from BB leaving the barrel before before full spring expansion but you're able to transfer more energy into the BB.

In my MP5K I installed a PDI 170% spring and it chronies at 360 fps with 0.2g BBs. That spring with regular sized AEGs puts out well above 400 fps, because of the spring strength though I've had to replace the stock TM gears, stock TM cylinder head, stock piston head (went with an aluminum, broke poly piston heads including Guarder and Prometheus) and the TM spring guide.

Hope that helps, that's what I found works if you want to get some serious fps out of the MP5K.

[Endymion]

The MP5K is a bit of a special case... it actually does use a version 3 gearbox. The wiring is a PITA, having the trigger assembly pop out on reassembly is a PITA, and trying to get enough compression to boost your FPS up to a respectable degree with the shorty ass barrel is a PITA. There's very little room to play with on the K.

[EDIT] Feh, Colin beat me to it.

[jerryliang2k]

I'm not really looking for a fps upgrade. As long as I'm shooting consistently, sub 300 is good enough for me

I'm looking to make the MP5K into a mini BB hose. Shoot off the 30 round magazine in 2 seconds . I imagine I'd probably play around with the gears and bushings. I hear the K can accomidate a 9.6 AK battery? That would certainly help my rof.

So in summary, it seems the difficulty with the MP5K lies in:
- assembly
- wiring
- fps upgrades

@ Colin_S
Did you ever get any metal recievers for your K? If so, how was that experience?

thanks for the input,

Zi-Xiao

[Colin_S]

My MP5K NIB chronied at around 240-250 fps, installing a Guarder SP90 increased that to 260 fps and the Guarder SP100 to 300 fps. It's the wife's main weapon and she was definitely complaining about the range with those spring setups, but I guess if you don't need a high fps it's not a big deal.

To get that ROF you might want to invest in high speed gears and a 9.6V battery will definitely help out. To get that to fit though, you'll need to take the stock cocking handle off and shave off space for an additional cell, otherwise the battery will not fit.

Yes I got a CA MP5K metal receiver for my MP5K but I haven't installed it yet. LOL it's been sitting on my desk for like 4 months but for some reason or another, never had the time. The quality of the CA MP5K body is not at the same level as other CA bodies to be honest, its light and the same weight as the TM plastic body. There are no markings but I still plan on installing it one of these days because it's metal.

[Maverick0]

I had no idea... I just assumed it was a 2. It looked a hell of a lot like a 2 when I saw it taken out of my PDW though.

[Mysteryfish]

nevermind.

[Colin_S]

Mysteryfish my apologies, my references were to the people above you who said the MP5K is difficult to work on and that it was a version 3 mechbox.

[ProbeJax]

Is there anything wrong with the K, or are we just talking about people upgrading it for the sake of personal preferance?

[safx]

http://cibban.se/airsoft/tech/ti_mechbox_guide.html