OK so my original TM HK51 is undergoing a bit of a makeover and I've just about finished fitting a RS wood kit to it. To echo someone elses earlier post, mine has also lasted me 7 years doing 325fps on the dot for around 80 - 100k rounds. I've never had one problem whatsoever with this beauty, however, one fateful afternoon of skirmishing meant a screw fell out of the motor plate on the base of the grip. This caused the motor to slip, make a horrible grinding noise and upon pulling it apart, the pinion gear had some wear to it.
So... I took the opportunity to do these external upgrades