Originally Posted by ThunderCactus
7.4v won't hurt the gun at all, however you should have the proper safety devices in place to make sure you don't cook your LiPo!
If you gun can't pull an M110 spring with an 8.4v NiMH mini, you should invest in a set of torque or super/double torque gears, and perhaps a stronger motor.
What brand/type of AEG are you using?
That's what I was thinking at first, but I used a car battery to see if it can pull it, and it did. The brand is AIM, but i have a SRC gearbox in it. The 8.4V mini is the stock battery, and I don't think the quality is too good on that.