I personally run 11.1 in my guns because the trigger response is key for me when shooting semi auto, If you plan to do a lot of spray and prey, then I recommend the 7.4 because it will lower your fire rate and reduce stresses on your internals. I've been using a stock ca piston with 11.1 for the past 4 years and never had any problems. It really depends on a number of factors including, wiring, motor and gear setup. As for "C" rating, it's more of an insurance policy to make sure your battery doesn't melt and explode. I've used 10C and 20C with 3000 mAh and only experienced heat buildup with 10c but it depends on your wiring and motor resistance.
Airsoft motors typically draw at most 40Amps of current at trigger pull, but only for a few seconds at a time, so you can get away with having a lower C value. To get the max rated discharge, just multiply your C value with your capacity in Ah. eg (10C with a 3000mAh= 30 amp max draw. 20C with a 2000mAh= 40amp)
Last edited by Windows; May 30th, 2013 at 08:12..