mp5k high rof budget build?

[Hectic]

Ok so im gettin a Cyma mp5k tommorow maybe the pdw version havent decided yet.
At any rate id like to eventually build it for a higher rate of fire. Say 30-40 rps.
How could i do this on a relativly small budget say under a hundred bucks?.
Swiss cheese the piston?
Maybe remove a few teeth from the piston (short stroke i think they call it)
I dont wanna go lipo so i guess just stick with the 9.6.
High speed motor? Gears?
Lookin to keep it cheap, simple and reliable.
Thanks in advance for any input.

[Matula]

Answer :


Echigoya is doing it for 252 $!

[Hectic]

Originally Posted by Matula

Answer :


Echigoya is doing it for 252 $!

Four problems with that.
No stock.
All plastic.
Fake bullets in mag.
And bein a TM the fps will likely be too low to import.
And a fith issue would be cost. By the time i pay shipping, tax and xuties itll be in ths $500 range. Im lookin at a 180 doller cyma and 100 in upgrades.
It is a nice gun tho just want something cheaper and more rugged for a sidearm while sniping. The metal cyma will be less likely to bust while draggin it around.

[iKliiu]

There's no way your getting 30-40 RPS without a LiPo. The easiest method to get that rate of fire is with a: 13:1 gearset, 11.1 LiPo with a high discharge rate and a neodymium high speed motor (SHS will do, Lonex is better).

However, you must correct AOE, swiss cheese the piston, and possible short stroke to avoid pre-engagement. Main thing with the MP5k is battery space, it is hard to find a LiPo that fits in there.

[Hectic]

Okay then what about a lower rate of fire. Say 20-30rps.
Ya i know the lipo would be hard to fit cause they mostly flat things all that really fits is a stick type bat.
Plus i just dont wanna mess with lipos yet once i do ill do all my guns then 8 need a bunch of fets and such too much work for now lol
I was thinkin 30-40 rps was a lil high just needed to put somethin as a goal.
So lonex high speed motor 13:1 gears swiss up the piston and maybe shave two teeth off the piston what kind of rof u think ill get out of that.
And set the aoe that is just setting the timing on the sector gear right? I guess it has to be advanced a bit with less teeth on the piston?
Also in regards to swiss cheesin the piston i should prolly start with a beter piston to avoid it falling to bits once the gun is firing or would the stock cyma one be ok?

[Spike]

You don't need a fet with a lipo, if you stick with a lower C rating... and you can get lipo batteries in all sizes, including stick type.

[Hectic]

So the voltage is all i need for rof not c rating? And yes i see the stick type lilos but ive also seen they dont quite fit in the mp5k due to the size/shape

[Stealth]

The battery goes above the gearbox, behind the charging handle.

[Hectic]

Lol thanks stealth.
Yes i know where it goes. If you look in the pic that is with a lipo stick in a mp5k the guy had to remove some screws and shift the lower and mechbox outta the way to fit it then it makes the holes for the body pin out of alingment

[iKliiu]

Stock CYMA pistons are beasts, start with swiss cheesing that.There are many guides on the internet on how to correct AOE. Also, there's a chance that the 9.6V might not have enough power to supply to the motor if you use 13:1.

If you want roughly 20 RPS, just get a LiPo and a neodymium motor. Still, remember to test AOE, shimming and swiss cheese the piston.

[MaciekA]

I've got the very same CYMA MP5K running at about 380fps at around 30rps+ or so.



To quote myself from the airsoft media thread,

Now has a King Arms gearbox, Lonex and SHS parts throughout (piston, piston head, cylinder head, 13:1 gears, etc), JG Blue motor, fatter wires, Gate GDS-4005 MOSFET, XT60 connectors... Etc.

Still no R-Hop since I want to field test it before moving on to that, but I did put in the "extend your range to infinity" REAPS bucking.

This build is all about power. To replicate it you will absolutely need a beefy LiPo, a MOSFET, and a strong spring because your barrel is very short and you will be stealing volume away from your cylinder with sorbothane. The stock cylinder is ported very very late and that's exactly how you want it. I didn't have much luck with my other type 2 cylinders, so stick with the stock cylinder until you find something ported as generously and forward-biased as the CYMA one. It is ever so slightly better-ported than anything else I had in my collection.

It's been many months since I did my build of this gun, but I believe it has an M130 or higher in it. This is to compensate for the starvation of volume. Works great. You will need a very good neo motor, I believe mine is using the JG Blue. Start with any neo you like though, and honestly you may want to start with one that's slower so you can get any kinks worked out (kill a piston, wonky feeding, etc).

I swapped the gearbox entirely King Arms V3 gearbox (swiped it from a SIG 556 rifle). The only issue with that is the firing selector isn't as happy on the KA gearbox as it was on the CYMA one. You may want to try something non-KA if you're doing a complete swap. Lonex for example.

For a power source, if you want high velocity (>360fps) and a high rate of fire and a very fast trigger response like I did, you are eventually going to have to face the cold hard reality that a small LiPo will not be able to push an M130+ spring on high speed gears.

Honestly, it is actually really difficult to fit any good and strong LiPo in this gun. I eventually gave up and instead externally mounted my battery. This works really well since the weighting of the gun isn't negatively-affected, but it's not something you'd hang on your side for a milsim:



A more long term solution is something like the following mockup I did a few months later:



I've got so many other projects on the go that this will have to wait for another day, but I do plan to do it eventually. The key for keeping this true to "K" form is the stubby stock -- yes, some people fit full size MP5 stocks to their MP5Ks, but I'd rather find a nice solution for mounting this stubby H&K 416 stock instead. I'll figure it out eventually. Then I can power this gun with a 6000mAh high-C LiPo.

Good luck with your build. Don't cheap out

[Hectic]

Awsome so now i know where to start.
Ill just swiss cheese sorbo and shave a cpl teeth to start with for a minor increase maybe a slightly lighter spring. Id like to get around 350fps so i can also use it indoors. Then ill just start savin up and build a lonex bassed high speed gearbox to eventually drop in
This will let u mount a buffer tube not sure if itll assist u in mountin yer stubby stock tho. http://shop.ehobbyasia.com/action-mp...marui-aeg.html
Good luck on finnishin up yer build lookin good so far.

[Hectic]

ok so instead of makin a new thread ill just revive this one.
i ditched the k for an sd6 (still cyma)
i did a high speed build for indoors and it came out prety good.
Cant recall all the parts but basically i did 13:1 gears, swiss cheesed a lonex red piston ans put a light spring in it (m90 round 310fps) it was perfect fornimdoors. maxed out around 28 rps with a merf 3.2 and a ln 11.1, 1100, 20c lipo. I figure its about the max the stock motor can spin?
so i want toake this an outdoor gun now and maintain or up the rof a bit. Im gonna stick a slightly longer inner in it and a modify 110 spring(should be 390-410 fps, prolly closer to 390 with a short barrel) so what do i need motor wise? A lonex a1, a2, one of those crazy tienly gt 3500 or 4500 motors? Still shooting for that 30 rps mark (for the trigget response not so much the rof) and around 400 fps.
lemme know what motor you think ill need. Also plan on the modify red piston head (incase i didnt replace the stock one yet)

[lurkingknight]

A1 or A2 will put it around 30-36 depending how it's shimmed. I just started doing builds for a few guys that have tienly motors, I'm not quite sure where they rate speedwise. One build ran 19:1 lonex gears from a drop in box and A2 and was like 36rps... another build used a tienly but shs 13:1s and was getting 36.

Something's not adding up between the 2 different gear brands, but both guns are shimmed beautifully, the A2 19:1 build is only drawing 16 amps while the 13:1 shs build is drawing 22amps. Both are whisper quiet.

Have a 2nd tienly build with a slightly slower motor and the 19:1 drop in gears on the bench right now that's waiting for assembly.

I don't think you can' go wrong with either motor brand though.

Mp5 mags start having feeding issues around this speed from what I understand.

[Hectic]

well with the merf i can dial down the rof after the first shot. 30 rps is fun for showwing off like "hey look what i built" but mostly just going for the trigger response. Dumping midcap down range in 2.5 secconds is prety useless for the way i play and alltogether imo. Trigger response close to that of a gbbr isnt lol. Id venture a guess that the rpm rating is at the lil axle on the motor not the gear, i mean 3500 and 4500 rpm is damn high lol.
so as far as lonex. A1 a2 or their budget motor?
also ill note that at the 28ish rps mark i had no feed issues on short or long cyma mid caps or with the high cap. Keepin up with winding and mag changes was the biggest pain lol. Lotta fun watchin a literal lazer beam of bbs flyin down range tho lol