When i was researching for my high speed setup i had to think abour the shimming and the wear ont the gears.
This is why i choose modify modular gear set.
No shimming and gears are in the perfect timming. As mentioned the piston was the first peice to break down. But i fired at least 10 000 rounds befor it happened.
the gears were showing no sign of wear, they are rock solid. And if you dont want to have to worry about shimming ther are perfect.
http://www.airsoftparts.ca/store2/in...roducts_id=690
and your right about the low power batt.
so using a 9.6v will give you what your looking for. (up to 30 BPS)