[m102404]

Awesome work and great write up! Nice to see someone put the time and effort into sharing their experiences with the rest of the forum in such a thorough way.

I'm not sure about the motor seating depth affecting velocity...even if the extra pressure of "over-seating" the motor resulted in slowing down the gears, when the sector gear finishes pulling the piston back everything but the spring and piston are removed from the "power" of the mechbox...so the piston should go forward as fast as it ever did. I could be complete wrong on this (I'm often wrong...but I learn fast!). You're probably experiencing the "Proud Papa" syndrome...where the elation of getting your rifle working in that sweet spot enhances all your senses...LOL!

There's definitely a sweet spot when the gear noise is the "deadest"/quietest when seating a motor.

If you have to work on the mechbox again...you can cheat and just hook the grip/motor up to the mechbox without having to install the mechbox in the lower receiver...saves time and reduces the number of nicks you might make knocking out and reinstalling the flora pin. You can still test the full function of the mechbox (safe, semi, auto) by manually moving/holding the selector plate.

Last note...are you using the stock TM mechbox shell? I've not had it happen...but there's plenty of reports here that it does not do well in the cold...

Great stuff!! Now the madness of building your next M4 from scratch begins...