Wits end over G&P m14 massive air loss
 

I have an issue that has to be the weirdest and hardest ive ever come across. Im working on a G&P m14, and no matter what i do, it shoots around 200fps, even on a m130 Modify spring.

Ive tested compression about a billion times, internally is fine, replaced the hop up rubber, replaced the nozzle, tried different springs, shimmed the Hop Up unit forward, shaved the tappet plate.

Im about to throw this out the window. I cant seem to find the issue. The air leak is Hopup-Gearbox but it shouldnt be there at all, but if i put bbs in the feed tube it shoots out.

I got it to shoot up to 375 on the m130 by accident once, but then it settled down to 200 again. If i hold the barrel in my hand and shove it into the gearbox i can get random readings of 460. So i know its hop up to air nozzle.

Im thinking its either wobbly nozzle syndrome, bad hop up misalignment or something else, but ive tried everything that has solved these problems in the past. Any suggestions or fixes guys?

This is out of my realm but did you try sealing the hop-up bucking? Like with teflon tape or dental floss?

Did you check air nozzle alignment looking down the barrel?

Assuming that your cylinder and piston and piston heads are properly sealed all that is left would be air nozzle. Is it the correct size of air nozzle? I once put M4 air nozzle in an MP5 and had feeding issues. In your case it is possible that air nozzle is too small.

Ill try that thanks!

did you replace the barrel? compare the original to the upgrade, specifically the locking lugs that align it in the hopup where it's clipped in.

since the g&p is tm m14 spec, it might need the special m14 barrel.

Any updates on what it was I'm having the same issue

My main issue was the lips on the bucking were to long and folded over. Trimmed them back and it works fine...indications that this could be the issue is random bad feeds.

believe it or not, however every m14 ive done work on has had that issue after replacing the stock rubber. the lips on the stock rubbers from what ive found are just a hair too long causing them to fold in upon contact with the nozzle (various marui base models as well as cyma ones as well

I fixed my problem by swapping out the bucking as others have stated. Same problem, no matter what spring i swapped it would stay at a steady 230-250 FPS.

Do not use the G&G Green buckings. Try a modify one instead and try the stock nozzle or a nozzle that is the EXACT size. Not +/- 1mm. Exact.

To find out if there is a nozzle to hop-up leak, put the gun upside down and put enough bb's in the chamber so that your thumb is able to make a seal over the hole with minimal space for bb's between the nozzle and your thumb. If you shoot and the FPS goes up, your nozzle is too short and the air is being vented out the magazine feeding hole.

If the fps stays the same then swap the hop up rubber. Either way, have fun figuring it out.