Air Leak?

[dpvu]

I'm having trouble finding the air leak causing a low FPS problem in my SPR build. It's a JG complete mechbox (new version with a MOSFET) and I also installed a Guarder Bore-Up kit into it. The piston head initially didn't seal well but I fixed that by adding some teflon tape around it and putting the o-ring over it. It seals very well with the cylinder now. The nozzle seems to have a small leak. When I take it out of the mechbox cover the hole and compress the cylinder, there is resistance but also a small leak. I can't seem to really fix this, some teflon tape has made it better though. The problem is when I put it all together, there's no compression. The nozzle provides zero resistance. I'm confident the cylinder head and piston head seal and the leak behind the nozzle wasn't that big. Would this cause an M125 spring to give ~320 FPS? If so, what's wrong with the nozzle? The inside o-ring is there.

Other specs are:
-KA hopup
-Prometheus hard hop-up rubber

[m102404]

1. Loosen off the stock screw a bit - test

2. Swap hopup rubbers - test

3. Swap hopup units - test

4. Swap nozzles - test

5. Sell for parts - (just kidding)

If the compression in your mechbox is ok (and all in all...a slow, very minor leak is ok most of the time)...then there's not much you can do about it.

A lack of airseal when the nozzle's forward (and it's hard to ensure it's completely forward after that first shot after the mechbox is closed) is from the nozzle not seating well with the hopup rubber which is held by the hopup unit. Can't really adjust any of those parts...so swapping them out is probably the most expedient.

It may be as simple as taking out your inner and rubber and reseating everything...it may not be. Start simple, change one thing at a time.

Sucks though trying to figure it out, best of luck,

Tys