Help: CYMA RPK (1st time upgradeing a gun!)

[Lockark]

Hey. 1st off I'm new to airsoft, and getting ready to order my 1st gun. I realy want a RPK, but have been told by others that if I'm going CYMA I will need to put money into upgrading parts and ect.

I have found detailed youtube videos showing how CYMA RPK's break down, and how to disassemble/reassemble V.3 AK gear boxes. At this point I feel comfortable about attempting to upgrading this gun my self, and feel up to the challenge.

So here are my questions:

1) I've been told from reviews I've read that the Gears and O-Ring in the CYMA RPK should be replaced from what comes stock. Is their any other parts I should upgrade from the stock gun? For example the piston?

2)I don't know witch brands of parts are the "good" and witch ones are the lemons. I was hoping people could sujest to me brands and retailers for these parts?

I'm looking at the VS parts mostly ATM, but if their is better please let me know!

3)Some reviews say that the stock M130 spring in the gun can shoot abit hot for some feilds. If I need to switch this spring out for something a step down to get the FPS legal, what spring would that be?

Thank you for takeing the time to read my post. =) I tried to make sure I did as much reading as possible, but had a hard time finding answers to these specific questions. Any and all advice is appeceated! This being my 1st time attempting something like this, I'm hopeing to learn as much as can from thows more experience.

[Phileas Fogg]

My cyma RPK shoots fine.
I dont know what an O-ring does.
Yes I had to have the spring downgraded because it would shoot around 450.
I believe the spring that was put in is a 90.
It shoots at around 350 -360 now.

[Rusty Lugnuts]

greetings My cyma's have both shot thousands and thousands and thousands of BB's and the mechboxes have not been opened. The airseal of the o rings is excellent and one of them is always 377 fps plus or minus 1 fps. What does need upgrading is the hop up rubber ( BAX sucks) and get some better mags . I suggest Lonex flash mags.

[lurkingknight]

downgrade spring to 400 fps... shoot it till it breaks and go from there.

and wow... if you don't know what an o-ring is for in an aeg... don't open one up. XD

chrono the gun first before opening it. With the slight change this year in importation regulations, guns from certain factories can come in without having big springs put in.

a 130 spring in that length of barrel is definitely going to be over field limits.... I would go with a 100 spring and see how it works out... at a minimum of 360 fps, if you have a full cylinder and super long barrel as an rpk should, you'll probably get a bit more than 360. If a 100 is too low, a 110 will put you really close, possibly over 400. Go with the sure bet of the 100 spring.

[Phileas Fogg]

I intend also to change the actual inner barrel taht is 500mm and exchange it for a 650mm as I understand it the innerbarrel it comes with is shorter than the outer barrel

[Lockark]

Originally Posted by Phileas Fogg

I intend also to change the actual inner barrel taht is 500mm and exchange it for a 650mm as I understand it the innerbarrel it comes with is shorter than the outer barrel

Now a local player who owns a CYMA RPK and has done alot of upgrades to it, told me the shorter inner barrel is not a issue.

Well a guy on youtube who does are of custome work on airsoft guys said he would swap the 500mm for a 650mm.

So I'm not sure witch one is correct on that topic.

[Phileas Fogg]

I saw that video, that is why I am thinking about doing it but, I wonder if it is in fact superfluous.

[Lockark]

I have no idea. I'm getting my 1st airsoft gun in a week or so. lol

Maby someone who knowen better can answer that too? lol

Originally Posted by lurkingknight

downgrade spring to 400 fps... shoot it till it breaks and go from there.

and wow... if you don't know what an o-ring is for in an aeg... don't open one up. XD

chrono the gun first before opening it. With the slight change this year in importation regulations, guns from certain factories can come in without having big springs put in.

a 130 spring in that length of barrel is definitely going to be over field limits.... I would go with a 100 spring and see how it works out... at a minimum of 360 fps, if you have a full cylinder and super long barrel as an rpk should, you'll probably get a bit more than 360. If a 100 is too low, a 110 will put you really close, possibly over 400. Go with the sure bet of the 100 spring.

Thanks for the advice! I haven't ordered any of the inner parts yet, accept for a 120 spring that I ordered with the gun thinking that would be a step down enough. I didn't realize I would probably need to go as low as 100 or even 90.


Well I guess I have one now if I ever need it in the future. lol

A Chrono is my next purchase along with any parts to tune it up. Then it's Kit/mags and all that jazz. (Or the Tactical Cos-Play if you will. lol)

[Bellerophon]

After about 500mm, additional barrel length does not really affect accuracy. It may give a slight FPS increase, but FPS ≠ accuracy.
Also, when comparing springs, "M" number (ie M90, M100, etc.) means meters per second. So an M90 spring should get you ~295 ft/s, M100 ~330 ft/s, and so on. An M100 is ideal for indoor use, M110 or M120s are good for outdoor use. Keeping in mind, I don't know what barrel length these spring ratings are measured at, with a long and/or tightbore barrel, you might shoot hotter than what I quoted.

[Styrak]

Don't do anything to it. Most likely it shoots great as-is. Only fix it if it's broken/not working right.

[Lockark]

I was just pointed out to me the verstion of the CYMA RPK I'm getting is a wood folding stock, instead of the Wood fixed stock ones I've always been seeing.

Is it possible to swap the folding stock for a fixed stock?

edit: Nvm. Just figured out it's not worth trying. lol

@Styrak: I'm going to have to pop it open to switch the spring, so figured it wouldn't hurt doing some other thigns well I'm at it.

[Strelok]

Nope, its based on the receiver.

The only thing I did to mine initially was downgrade the spring. But then I pimped it out for a high speed ROF setup, as well as a tuned up drum magazine to keep up with the thing.



Also popped on a PKA sight for it just to make it look crisp .

Theres nothing wrong with the folding stock style... I actually wish mine was like that time to time.

[Lockark]

Originally Posted by Strelok

Nope, its based on the receiver.

The only thing I did to mine initially was downgrade the spring. But then I pimped it out for a high speed ROF setup, as well as a tuned up drum magazine to keep up with the thing.



Also popped on a PKA sight for it just to make it look crisp .

Theres nothing wrong with the folding stock style... I actually wish mine was like that time to time.

Great pic! Gun looks slick!


Also good to know. I ordered a Drum mag for mine also actually. What does Tuneing up a drum mag involve? Is their any Videos or articles detailing it you could direct me to? (I ordered a CYMA drum mag, so I assume it will be fine. But I still want to know this stuff! lol)

Sorry Im super obsessive about this stuff. For me working on this stuff, maintaining and tuning it up seems like it's going to be half the fun of this hobby. lol

edit: From what I've been told the folding stock version does not have the side rails for mounting scopes on. I wasn't planning on useing a scope, but now it's totaly going to bug me. lmao.

[Rusty Lugnuts]

There are scope mounts that do not use the side rail, One type bolts on using the two screws in front of the mag well and one screw from the sight as well as a version that replaces the dust cover with a cover thats railed etc. AS soon as your Age verified we can tell you where to buy them. Please don't overlook the most important upgrade, your hop up rubber

[Off_kilter]

those screws are not present on the CYMA RPK. Only on TM style AKs.