Battery question
 

Hi! I'm wondering if this:http://img119.imageshack.us/i/photo0384.jpg/ could fit into an M4 full stock?

I belive that size of battery is designed for the M4 shorty full stocks, not sure if it would fit a regular full stock

That battery is for a PEQ battery box. It's too wide for the battery door on a full stock, though you might be able to squeeze it into the stock after taking the door off. You're much better off just getting a large battery though. All else being equal, larger cells are better cells.

The reason for this type of battery was because I wanted to try out a PEQ and in case I didn't like it, I could still use the battery.