The magazine itself is divided into two sections: tube-like chambers containing pellets and the battery. As shown in "the 7 wonders of Crysis 3: Episode 4" pellets are stored inside the tube-like chambers without any propellant between them. However, the Typhoon most likely incorporates both electromagnetic and Metal storm technologies.
Players are able to carry two whole magazines (a total of 1440 rounds).
It is first seen in the Crysis 3 E3 2012 demo (with a reflex sight mounted). The Typhoon features a 720-round tube-like chamber magazine that supports extreme 30,000 rpm rate of fire that drains said magazine very quickly.