The AN-PEQ attaches to weaver rails. However, if I were you, I would get a gun that was wired out the rear and throw a crane/MOD stock on it. That way, it will be easier to get an upgraded battery, and you don't have to worry about getting one to fit in the PEQ box. Also, crane stocks just look bitchin.
In other news, Ganef, what kind of suppressor do you have on that rifle? Is it the Guarder OPS SPR, or something else?