correct, a battery sling as one of many ways to fit large batteries in small guns.
when it comes to batteries, more mah = better
more mah can slighty increase ROF....but only slightly. Someone described it as a bucket of water. voltage is the hole in the bottom and mah is the water in the bucket. the more water, the more pressure...it wont really come out that much faster, but it has alot more force behind it. I dont know the science behind it and I am no expert on batteries, but i can tell you from experience, if you run a 9.6v 600mah battery and then a 9.6v 3300mah battery in the same gun, the 3300mah runs faster.
8.4v is a safe number..some will say you need a 9.6v to run upgraded guns...but i have turned a 190% equlivant spring(470fps) with an 8.4v no problem.
9.6v is fine also, but you really wanna have metal bushings and sooner or later your gonna need new gears.
many guns that say mini battery can take a large battery with some mods. be it modifying a stock, adding a slightly larger frontend...the readymag battery system, the AN-PEQ2 battery box setups...and now the Star M800 Battery Carrier
