FPS issue's. Need help

[SnakeDoctor87]

Hey guys,

I need help. My G&G Firehawk has had an issue with the fps dropping. Its started off nicely about 300ish on .2s for cqb when i bought the gun 2nd hand last year. Its been Shooting fine but the fps has been dropping and has now settled around 180ish on .25s. I have reshimmed the gearbox and installed a perun v2 mosfet with pre-cocking active.

At first I thought it was the spring so bought a new m95 spring. The current one being an m90. I had to reduce the stock spring as when I reshimmed it I cleaned all parts and re-greased it putting the fps up to nearly 390 fps which was way too hot for my cqb site. Putting the m95 in didn't change the fps in anyway.

So I started to suspect the air seal of the original G&G parts. So I replaced them with a full upgrade kit by madbull. After fitting this the fps remained the same and the new nozzle was causing a misfeeding issue. I fixed the misfeeding issue by using the G&G nozzle with the madbull components.

I researched some more and found that fps drop can happen if the seal between the nozzle and hopup bucking is rubbish so i replaced the hopup bucking and still the fps remains the same at 180ish. I have noticed that the fps is constant at 180ish.

Does anybody know what I may have missed or is there a terminal issue with the gun? I've spent a good portion of money to upgrade this G&G and cannot seem to be able to resolve the fps issue now.

Can anybody help before I give in and pay a tech to look at it please?

Thanks in advanced.

Snake ?

 

[Nick G]

It's got to be loosing air from somewhere , what bucking did you fit ? have you tried a compression test of the piston in the cylinder ? could be the piston o ring or the cylinder head o ring (s) at fault. Did the fps drop happen immediately after you had worked on the gun ? something may not have gone back together properly.

 

[Prisce]

I don’t like the Madbull parts, not built to the highest tolerances. 

But, reading what you’ve put. I’d say the spring your using isn’t correct. Put the stock one back in and then chrono it, if your up near the 390ish FPS again you will know for sure it is the spring you have installed.

Have you done any of the air seal checks? Lots of them around, will let you know if you have a leak, and roughly where it will be.

 

[Sneaky]

Check to make that that the aeg has correct air nozzle installed, as that can have an impact with regards to air loss.

Also clean all the parts before putting the gearbox together.