G608-4 low fps

[Chicken pie]

Hi. 

Had a g608- 4 for a few months and all was fine.

Then a couple of weeks ago it lost a load of fps / power.

It was running about 180 - 200 fps with .25g.

 

A barrel clean, checked battery charge ( 7.4v) and discovery of part worn foam/ sponge in silencer, which was removed resulted in fps increasing to about 250fps.

 

But it's still lower than when new and bb (.25) are dropping at about 30m at best. Tried winding hop up, no real advantage in range.

 

So what could be causing the low fps and what's needed to get power / fps back up to 300 plus?

 

Thanks

Edited November 13, 2021 by Chicken pie

[BigStew]

are you chronoing with the suppressor on the gun? unless you have an extended inner barrel to the front of the suppressor the bb will be losing FPS travelling through the suppressor. chrono the gun with out the suppressor 1st. also 250 with 0.25 is equivalent to 280fps with 0.2 bbs not sure you have actually lost any fps at the point. please clarify how you chronoed your gun? 

[Chicken pie]

If I remember I chronograph it with suppression on ànd off. Results were much the same.

 

I'll check it again Monday to be sure.

 

It's definitely not got the range it had a couple of weeks ago.

Edited November 13, 2021 by Chicken pie

[Badgerlicious]

When my l86 lost a ton of power it turned out to be the nozzle o-ring being worn down. Check the bucking looks good and is positioned correctly. Could also be the piston head o-ring, 

[Chicken pie]

Ok thanks.

I'm new to all this.

 

Hence I just discovered its actually a G608-4

 

So I won't ask my son again " which gun is this" !!

[ak2m4]

ideally you'll need to open up the gearbox to check the components, do a full inspection etc.  if you're not ready to open it up then you can check the hop rubber (bucking).  

[Rogerborg]

First thing I'd do is to get some silicone lube (liquid or spray), take it apart, and put the lube up the nozzle and swish it around.  Then I agree with checking the hob rubber while you let the lube sink in.

 

Then blow the lube out of the nozzle with an auto burst (which should also get some on the nozzle o-ring if you have one) until it shoots clear and dry before re-assembling.

 

Might help, might not, but it's quick and easy to try before stripping the gearbox.

[Chicken pie]

New bucking seems to have worked for the " hop"

 

But my fps on the chrono is still a bit low.

.25 @ 260 avg.

 

So next task is to get fps up a bit.

Any ideas.

Gun is currently stock bar the change to g&g bucking.

[ak2m4]

JG's use very cheap springs, they generally are quite thick and short, made from cheaper "piano wire", hence can degrade quickly.  Firstly you want to grab a new spring, ideally grab one which has been tested by the seller so you know what to expect, that way you can rule out issues. 

 

260fps with 0.25g is pretty low, that's around 290fps with 0.2g.  My guess is you have a couple of issues with the airseal together with a degraded spring.   Does the AEG use a quick change spring?  If so that's the easiest route to increase without opening the gearbox.

[Chicken pie]

Ak2 thanks

 

Asit happens the gun went dead Sunday. 

We thought it might be battery but it's not.

So once I have looked at dead issue,spring will be my starting point.

Thank you.