Godspeed, you're going about it the wrong way.
You can always swap out the battery packs if they run out, it's just like changing the batteries on a remote or MP3 player or calculator.
Pick your gun first and then figure out about how you're going to store the battery. In my M4 I have it front wired and stored in a PEQ/Battery Box.
So lets say you have an AK with a stick battery that's 1500 mah (lets assume 1 mah = 1 shot more or less). In half a day lets say you take 1500 shots draining all the juice from the battery. Well what are you going to do? Just switch out the batteries like on a graphing calculator! This would mean however you need 2 batteries at least. Now on the other hand lets say you have a 2000 mah large battery somewhere and take 2000 shots in half a day, well you're still going to need 2 large batteries to keep going for the day.
Now step it down to something more reasonable, lets say 600-700 shots in half a day of playing that's about 1200-1400 shots in a whole day, well in that case that means that BOTH the stick and large battery will be able to last you for a day and you'll only need 1. NOTE: It's still a good idea to have 2 batteries just in case you forget to charge the other one before a game or if for some reason the battery dies randomly.
ಠ_ಠLess QQ more Pew Pew
READY TO >> RACE