Originally Posted by Tankdude
7.2 volt 3600mah battery packs work fine in stock guns. I know because I use them. ROF is the same.
You need the amps thou when using 7.2 volts, so use 3000mah or higher.
7.2 are easy to find at rc stores.
Yep, I use a 3000 mAh 7.2V in my M249 with a 400 fps spring. Gets around 800 RPM.