so little velocity with such a setup??
 

Hi everyone, I bought a used King Arms M4 and decided to upgrade it.
The problems is I’m having only 233fps (constant) with this setup….
I never chrono the gun before the upgrade but I don’t know why it chrono like this.
The gearbox is shimmed the right way.

This is my set-up:

WiiTech Air-tight Nozzle, M4 Series

Hotpower 11.1V, 15C Lipo

JingGong Silver Wire Assembly With MOSFET

FMA "NOVESKE"+ -14mm Silencer (4'', CW, CCW)

Modify Professional 2-Ring+ Hop Up Bucking for Modify Hybrid Inn

Modify Hybrid 6.03mm Precision Inner Barrel 407 mm

Wii Tech M110 Spring

Lonex A2 TITAN Orange Infinite Torque-Up Motor

Lonex Enhanced Super Gear Set - High Speed Ratio (16:1)

Lonex Extreme Toughness Piston (10-Teeth - Burgundy)

Lonex POM Ventilated Piston Head

Lonex Aluminum Cylinder Head for Ver. 2

Dean everywhere

I must say that I put Mobil bearing grease inside the gearbox which I know it's not ideal.

Any idea how to diagnose this problem??

Thanks

Sounds like compression issues. Check the hop up (teflon tape if your friend), as well as the piston (open up the gearbox, take away the spring, push the piston all the way to the cylinder head, cover the nozzle with a finger, then try to pull out the piston).

You'll actually want to install the nozzle ant tappet and hold them I the forward position then try to put the piston forward to check for compression.
but yes sounds like air leak. What cylinder are you using, where is the port located?
And yes could be a hop up leak someplace as well.

Try this: https://www.youtube.com/watch?v=v1i5rCMiueE

Be sure to check the seal between your air nozzle and hop up unit as well. Sometimes the specs between brands are different and can result in poor seals. If you have another hop up unit try it out. You can lose a surprising amount of air pressure between those two points.

What cylinder do you have? And if it's ported, is the port towards the rear of the gearbox where they should be?