[FNG]

I beleive that my M4 is demon posessed. Or...I'm an idiot...could be both.

First a little history of the gun then on to the whole demon/idiot thing.

I bought the gun used but nearly new in stock form. Afterward I upgraded the spring and bushings, reshimmed it and put in a 20A fuse. It was an unknown spring but it brought the FPS up to 395-400. It was gamed with a few times and performed flawlessly....then it didn't. I had already decided to switch out the spring before the mechbox went kablooie anyway so now was as good a time as any. Little did I know that the demon (or my stupidity) had already taken hold.

This what the gun does:

With a fresh battery (mini 8.4 or 9.6) it will fire about 40 rounds then start to feel sluggish, the battery heats up then it stops firing. The spring will be near fully compressed but it will not crank past that last tooth to release the piston. You can hear and feel the motor struggling to turn but it doesn't.

This is what I did:

I openned the mechbox and tossed that spring. Cleaned all the gears and inspected them, no wear was present on any of them, the motor or piston. I reshimmed it again thinking I screwed it up the first time. I then installed a PDI 150 spring, regreased and reassembled the gun.

The poltergeist laughed and it did exactly the same thing as before.

So I scratched my head, got that stupid look on my face, had a beer and decided to try again in the morning.

After taking it apart again, visually inpecting all the wiring and cleaning all the contact points. I reassembled the gun now with a Gaurder SP100 spring.

Again the demon laughed. It did exactly the same thing. Fires 40-70 rounds, starts to become sluggish, battery heats up and it stops firing with the spring almost completely compressed.

Does anyone have any insight as to what I've overlooked, or done incorrectly?