Thanks for the info, guys, I appreciate it.

9.6 nicads/nimh is safe enought for your gun with good rof. Just proper shimming, change to metal bushings, use a spring guide w/bearing (better if metal), then you are good to go. What i like about using low fps springs is lesser maintenance. if you want to be more safe and if you have a budget, use CA STU gears, it will lessen the strain on your motor and piston body, but you will lose a lot of rof. I had a Cyma 035 AK74su, running on stock springs, stock gear, eg1000 motor and an 11.1v 12c lipo, still running great after emptying 3 bags of bb's @ 1000rpm. Trigger response is great. you have to use sector chips though to prevent misfeeding.

The reason for asking about lipo's is to stuff the battery in an M4 RIS without having to use a battery box. Thanks for the info on the gears