jg m16A4 battery upgrade

i just bought a 9.6v 4500 mah large battery for my jg m16 and did not relize it was longer than the one i have now.

1. will this size difference be a big issue?

2. if it wont fit in the butt of the gun what r some ways to fit it in there

1) The battery is larger than the stock 8.4v because :
A) The increased voltage adds a "cell", or the thing that looks like a AA battery.
B) Four Cells = 8.4 | Five Cells = 9.6V

2) It should fit in the butt of the gun without modification, if not I am not very familiar with the M16 stock, I always used the M4's with Crane Stock

k thanks