middle teath stripped on piston

[freewheelin4eva]

well let me see, I bought my gun used, and I am quite new, but it was supposed to be profesionaly cleaned and shimmed, with systama internals and a M100 spring. has a tm1000 motor. and am using a 9.2 v batt.
the gun has had maybe 5000 rds through it. varying full auto and semi.

now the problem is that I was playing, handed the gun off real quick to someone, they used it for maybe a minute, handed it back, the next shot I fired nothing, and it sounded weak, batt wise, thought it might be jammed, flipped it into full auto, nothing coming out still, then grinding, and then nothing. pulled apart, looked at batt, neg coming off of batt to deans conector, was holing on by a strand or two of wire. came home, pulled gun apart, making sure to keep track of shims and everything else. found that all gears looked good, motor's com. and brushes look great. runs good as well. but found that starting at the large tooth in 8 teeth, are all stripped, but the middle of these seven being the worst. so teeth 3 through 6 being the worst.
I tried to search, but am wondering if this was caused by the lack of power from the poor conection, or should I look somewhere else.
also what sort of grease should I put on the gears when I put it all back together and how much, it sure does not look like there is much in there.
thanks for any info and insight.

[ILLusion]

That shouldn't have anything to do with your power source. Seems there's further investigation required.