Evike.com show the AW Custom Gas Drum Magazine series for those who miss using hi-capacity magazines but prefer your gas blowbacks... "If you were to shoot 300 rounds out of a GBB pistol, you would need to reload about 9 times. With the AW Custom Drum Magazine, you wouldn't need to reload at all!!  With a BB capacity of ~400 rounds and a HUGE gas reservoir,  reloading seems like a thing of the past."