Actually, blasters were allways described as having a supply of gas inside. For example, the E-11 is said to have 100 standard shots in its power pack, with enough gas for 500 shots within the weapon.
Power packs are often clearly visible protruding from blasters, but we've never seen the gas reservoirs being changed.
Again, I call attention to the peculiarity of the red object being inserted into the inside of the weapon's "breech", as opposed to attaching to an external "magazine well".
Why would a power pack be put in such a difficult to access location (requiring the weapon to be hinged open), when it can be placed into a port on the external, as with all other combat blaster designs we've seen?
This just might be one of the gas reservoirs we've heard about.
Adding to this probability is the fact that we're seeing it being inserted into the weapon before the troopers enter a combat situation, and it's in a somewhat more difficult to access place compared to a power pack which would need more frequent changing.
Not that it's relevant , but the power pack and that red object really don't seem to differ much in size relative to the clones' hands.
http://s7.photobucket.com/albums/y257/C ... nnery8.jpg
http://i7.photobucket.com/albums/y257/CykeIsMe/red.jpg"..history has shown the best defense against heavy cavalry are pikemen, so aircraft should mount lances on their noses and fly in tight squares to fend off bombers". - RedImperator
"ha ha, raping puppies is FUN!" - Johonebesus
"It would just be Unicron with pew pew instead of nom nom". - Vendetta, explaining his justified disinterest in the idea of the movie Allspark affecting the Death Star
