I'd say no, but this one http://www.componentshop.co.uk/11-1v-1000mah-20c-continuous-discharge-airsoft-lipo-battery.html should. Assuming a milspec buffer tube (which is the smaller of the two) you would have somewhere around 27mm ID to play with. The battery I posted is less than 26mm diagonally so you should be ok. Bit tight but OK.