Lowering the FPS of GBB

[SeniorSpaz87]

Hello,

My first decent gun was a G&G CM16 Raider GBB. I quite like it, and have decent equiptment for it. My issue is that it shoots way to hot... i play almost exclusivly at The Mall, which has a 328 FPS limit, and my CM shoots around 350-360. I am considering spending a decent chunk of cash (for an unemployed 18yo) on some new gear for it, but if I do, then the FPS NEEDS to come down to at least 330. Pics will be attached in a minute, gotta go take some of the gas I use. It is rather standard, I think. Also, some people have mentioned some npas thingy or something?... No idea on that though...

Any information is helpful!

Thanks,

Spaz

*Edit: I have attached pictures.

The first pic shows the gun, with a nice dual mag system and the Safariland GripPod and SuperStoc

The second pic shows the two gasses I chronoed it at 350-360 with

The third pic shows the newer gas I have (The Mall's gas) and a lubricant gas that some say can be used to lower FPS, not sure if that's true though... Neither have been chronoed before though.

 

[PT247]

what gas are you using?

 

[PT247]

easy solution would be to use a lower powered gas, or you could fit a wide bore barrel to it?

 

[SeniorSpaz87]

OK guys, pics are up. I am a complete noob when it comes to this kind of thing, so if you have any suggestions, please either provide an in depth explanation, or for products, a link please.

 

[PT247]

if 144a doesn't lower the fps from when using green gas then somit is weird. Get it chronoed on the 144a

 

[SeniorSpaz87]

ok, also, you mentioned a wide bore barrel, what is that (guessing a wider internal barrel, therefore more gas escapes, and less propels the shot) and should I look into getting one?

 

[PT247]

Yup, lots of people go for tightbores as an upgrade but they also increase the fps. Gas guns work differently to AEGs and some say a widebore is bestI have recently fitted a widebore barrel to my GHK G5, not tested it yet but def lowers fps, supposedly increases effective range and accuracy as a bonus in gas guns!

 

[straffham]

ok, also, you mentioned a wide bore barrel, what is that (guessing a wider internal barrel, therefore more gas escapes, and less propels the shot) and should I look into getting one?

May be worth reading through the GBBR thread as there is some discussion on wide bore barrels there, yes in theory you will lose some fps as gas can escape around the bb as it travels along the barrel.

But worth chronoing on 144a gas first as that may well solve your problem.

There are ways of modifying the floating valve in the blow back chamber to restrict the amount of gas flow (basically achieving what an NPAS valve does in a less technical or tuneable way) which I've done on a couple of guns with good results, but only because specific fit NPAS valves aren't available for them afaik (SRC AKS74U and KWC Mini Uzi).

 

[Samurai]

I don't know if there is a G&G compatible NPAS, but if there is, then that's the way to lower the fps.

 

[jcheeseright]

Definitely no NPAS for the G&G GBBRs, they use drop-in GHK kits.

I expect the easiest way would be with a wide bore barrel, since opening the gun up to fiddle with the blow back unit / nozzle would be a massive pain in the ass.

 

[SeniorSpaz87]

yea, cant find any npas for G&Gs. in terms of wide bore barrels, what should I get for a short G&G CM 16 Raider GBB?

 

[GiantKiwi]

since opening the gun up to fiddle with the blow back unit / nozzle would be a massive pain in the ass.

There were mentions of porting the back of the unit a while back on one of the US forums - having actually tried it, its feasible, but yes, a complete pain in the ass - And not an exact science, I ended with a unit doing 270fps on propane, but then you've got cycling issues beyond belief.

yea, cant find any npas for G&Gs. in terms of wide bore barrels, what should I get for a short G&G CM 16 Raider GBB?

PDI 6.08mm // Orga Magnus 6.13 or 6.23mm. AEG type barrel. Length wise 233mm. Regardless of which route you go, you are looking at £75-100 of inner barrel in a £100 rifle. Having spent a lot of time, money and effort testing various widebores in various platforms, your best bet is likely to be an Orga MagnusHD 233mm length, 6.13mm diameter - which are roughly £75-90 dependent on the source, but that will bring you to about 330fps.

IMHO, sell the gun on, the extra cost to polish a turd just isn't worth it.

 

[SeniorSpaz87]

Meh, Ive gotten so many extras for this gun... Got a bunch of stuff that cant work on anything else right now, and a bunch that could... Got a $79 Rogers Super-Stock Deluxe and a Dual Magazine Coupler for $25 that both only would fit M4s, a Rogers Single Point Harness + Adapter ($35 + $10), GripPod GPS-02 that costs $150, and a Safariland Rapid Light System that costs another $97... Also got a DBOYS M203 for £60, and a B&T silencer/tracer. In order to get enough from this CM16 to get a new M4 for these items, I would have to sell most of this stuff with it... Something I dont really want to do. Also, the silencer, SPH, and light. i also mount on my P90, so those wouldn't go. So to get a new, better M4, i would have to A, find a buyer for a two tone (will be painted in a few weeks when it warms up and I get my UKARA regestration) G&G CM 16 Raider (Short) with 4 mags, which shouldnt be too hard, AND THEN get quite a bit more cash in order to get a new, high end M4. Also, it would be good to note that I am an unemployed 18yo who gets his cash from babysitting rich people's kids, as well as Birthdays and Christmas, neither of which is gonna happen soon. So, its not out of the question, but would be difficult and time consuming. Anyway, I just wanted a faster solution that selling my current M4 and getting a new one, as I have the game I need this for on the 22nd. Sorry if that seemed a bit rant-y; I just dont think I could do that right now. Also, I won't be getting any high end guns until I am UKARA registered, which I can't do as of yet.

 

[jcheeseright]

Woah woah woah... you spent $150 on a grip pod?! you're aware you can pick them up NEW for like £40?

Looks like you're strapping a lot of money onto a really quite cheap gun.

Remember, you can't polish a turd, but you can roll it in glitter.

 

[Lozart]

ALL that M4 compatible stuff can be swapped to A N Other M4. That's the beauty of it.

Regardless, try running it on 144a before you start panicking. You might not need to spend anything else on it.

 

[SeniorSpaz87]

Yea, had decided on the 144, as you know Lozart. And to the comment on the Grippod... First off, I like the real stuff, not the china knockoffs (although some of them are quite good). Second, anyne who has viewed some of my other posts knows I am close to Bill Rogers. He sends me stuff from time to time to test in the airsoft market (at least thats my excuse). So I basically pay import tax, and thats it. If I chose to sell that stuff, there is a large chance for profit, as all this cost me only around £60... But Ive kinda grown attached to it.

And yes, I am planning on eventually moving onto guns from companies like ICS, TM, and like brands, but first im worrying about getting into college, and possibly finding a job... Then ill focus on my "toys".

 

[jcheeseright]

When I said about getting a grippod for £40 I meant a real one, I don't buy knockoff airsoft stuff when the real thing is affordable.

 

[Mr Monkey Nuts]

Is that 360 FPS standard across all magazines?

There was a 1j bolt kit for these iirc, I'm on my phone but will double check later.

 

[GiantKiwi]

Is that 360 FPS standard across all magazines?

There was a 1j bolt kit for these iirc, I'm on my phone but will double check later.

There was one, but neither GHK nor G&G make the gearbox or spare parts for these any more and haven't done for over a year. It had to be ordered direct from Samoon, and they don't stock them any more due to them being discontinued.