Lower than expected FPS: King Arms M4

[MaciekA]

Originally Posted by m102404

...he could have his hopup cranked on a lot, which shaves off tons of FPS

Jesus... here we are theorizing the crap out of this and it could just be a cranked up hopup and 0.28g BBs..

[m102404]

LOL...I was saving that simple one for later, after he'd taken apart his mechbox and scratched his head some more...I'm just mean that way.

[Carlito564]

The hopup is completely open and I'm using .20g bbs for the chrono which is an Xcortech X3200. When I chrono the gun I do my best to keep it straight and I put the barrel of my gun half an inch to an inch from the chrono entry. Gearbox is shimmed, AOE'd, lubed, and air sealed pretty good so I don't know.. This AEG is making me rage

[m102404]

It's a PITA...but go back to basics.

1. Revert the mechbox to stock...chrony it.

Change one thing at a time.
2. Change spring...chrony it and see that you're getting your old stock FPS. You might have got a bad/mislabled spring (all the Modify packages between S100 and S120 are green...only s90 and s150 are yellow and blue).

If it's all good...then start on other changes, I'd go in this order:
3. Spring guide + Nozzle...chrony
4. Cylinder
5. Piston head (I know some guys swear by those...but I don't need them and don't think it's necessary at sub M130 power)

[Carlito564]

Finally got around to disassembling my gun and found that the problem was that I got shipped the wrong spring. I tossed in my stock spring which was rated for 350-ish FPS and that's what I got. So that was a big waste of time.. hahah