FPS too high out the box?

[Mr Dad]

Hi all. So got me a new G&G cmf-16 changed the barrel to a 6.03 and the hop up unit plus nozzle. Used it for the first time for target practice and I’m very happy. Only used sniper rifles up till now but the G&G the FPS is just to high for the field I use (328-350fps 1-1.1J) it’s currently crono’ at just above on both. What can I do to lower them so I can safely know I’ll be ok on the day. 
 

Thank you all. 

 

[Speedbird_666]

So got me a new G&G cmf-16 changed the barrel to a 6.03 and the hop up unit plus nozzle.

Wait whuuut? - you cracked open the gearbox to change the nozzle on (I'm assuming) a brand new gun? Do you mean the hop up rubber/nub?

Whilst a Combat Machine's barrel is made from what appears to be compressed tin foil and should be amongst the first things replaced, the stock hop unit/rubber work just fine out of the box. But horses for course n'all that.

Anyway...

If you are *just* above your site's limit (say, 10fps or so), load some hi-caps up and put a thousands BB's down range. The spring should settle by itself.

If you are well above the limit (20fps), then you'll need to either cut/replace the spring - assuming you don't want to revert to stock components.

Oh, and welcome to the forum....?

 

[Mr Dad]

Hi there. And Thank you for confirming what I thought. Off to get some shots off ??
 

as for the nozzle, yes I replaced the nozzle as I was unsure of the length on the stock one. I replaced the hop up with a maxx sport tracer unit for a few reasons 1. Shiny toys ? 2. (This is the main reason) to shut my sons mate up who said they where impossible to fit right and make them work. I call that challenge excepted ?. Yes the bucking and nub was also upgraded for no other reason than why not. As for the rest all stock. 
 

 

[Les]

Hi, 

I'd second that advice, I have a specna M4, with a few basic mods, hop up, rubber, nozzle, cylinder. I was struggling to get to a good FPS level- with the stock spring I was way under but with a 95 spring I was over!!  The chrono guy advised firing off a load of rounds and it stabilized just under the limit ?

 

[Rogerborg]

(This is the main reason) to shut my sons mate up who said they where impossible to fit right and make them work. I call that challenge excepted ?. Yes the bucking and nub was also upgraded for no other reason than why not.

The very best of reasons.

Indeed, in the context of wanting to play with toy guns, there are very few bad reasons.

 

[Tommikka]

The very best of reasons.

Indeed, in the context of wanting to play with toy guns, there are very few bad reasons.

‘Because I can’ is the finest reason for doing anything

I’m proud to be able to claim that I was referred to as one of “you crazy guys” by the mad scientist of paintball, Dave ‘Gommie’ Walton (RIP), due to my pistol mounted under barrel HPA air cylinder and other builds 

 

[Badgerlicious]

I replaced the hop up with a maxx sport tracer unit

If it has a better seal than the stock one it can certainly cause an fps jump. Replacing mine gave me about 10fps. 

One method to reduce fps is to put tape on the front of the gearbox to create a slight air leak. 

 

[Lozart]

One method to reduce fps is to put tape on the front of the gearbox to create a slight air leak. 

View attachment 80021

 

[EDcase]

...One method to reduce fps is to put tape on the front of the gearbox to create a slight air leak. 

Errrr, what?

 

[Badgerlicious]

?‍ it loosens the airseal and reduces fps. It's not a permanent solution but it'll do in a pinch. 

 

[Shamal]

?‍ it loosens the airseal and reduces fps. It's not a permanent solution but it'll do in a pinch. 

How do you mean?

 

[Badgerlicious]

How do you mean?

Across the front of the gearbox, above or below where the nozzle comes out, some very thin tape to weaken the air seal between the gearbox and the hop unit. Might need more, might need less, might not work, it depends where your other leaks are. 

 

[Rogerborg]

View attachment 80021

It's not a great method, but in a pinch, it can work. I've verified it with my borderline hot CYMA, in case I need to do it on site.

Of course, it being airsoft, "in a pinch" is likely to become "long term fix".

 

[EDcase]

Oh, I understand.

Yeah, I guess that could work but may cause feeding problems.

I had a slightly hot (+~12fps)JG SA58.  I did a quick pull on the trigger in auto a few times until I got it to stop mid cycle then left it like that for a few weeks.

It works but takes some time of course.

 

[Rogerborg]

Yeah, I guess that could work but may cause feeding problems.

I'd also suggest it as a bodge to ameliorate feeding problems, given that they tend to occur when the nozzle is too far forwards.

I'd stress the very bodgy nature of it, but in the end it's just shimming to sort out ropey airsoft tolerances, and nobody thinks that's unusual or unnecessary inside the gearbox. 

 

[EDcase]

Yep, I suppose the distances involved would affect the air seal far more than the feed mechanics.

 

[SBoardley]

Oh, I understand.

Yeah, I guess that could work but may cause feeding problems.

I had a slightly hot (+~12fps)JG SA58.  I did a quick pull on the trigger in auto a few times until I got it to stop mid cycle then left it like that for a few weeks.

It works but takes some time of course.

Dude that’s so lazy…..I love it!

 

[Godly]

You just need to replace the spring .