Patent ID: 7568421

Claim:
A cartridge feeding attachment for a firearm having a cartridge chamber and a muzzle comprising: a housing attachable to said firearm having means for guiding a stack of cartridges sequentially into said cartridge chamber along a first line of travel intersecting said cartridge chamber, a follower engageable with a rearmost one of said stack of cartridges and means disposed between said housing and said follower for biasing said follower along said first line of travel to feed a foremost one of said stack of cartridges into said cartridge chamber, when said housing is attached to said firearm; a sprocket supported on said housing having a plurality of circumferentially spaced recesses each receiving a cartridge of a cartridge belt trained over said sprocket, and a rotational axis positioned so that upon rotational indexing thereof, a cartridge of said cartridge belt will be positioned along a second line of travel extending between said follower and said rearmost cartridge of said stack of cartridges; means displaceable along said second line of travel between a retracted position out of engagement with a cartridge of said cartridge belt positioned along said second line of travel and an extended position engaging and displacing said cartridge between said follower and said rearmost cartridge of said stack of cartridges; means for biasing said displaceable means in said retracted position; means for transmitting the force of expanding gases resulting from the firing of a cartridge in said firearm to said displaceable means, operable for displacing said displaceable means between said retracted and extended positions, against the action of said biasing means; and means responsive to displacement of said follower upon actuation of said displaceable means for rotationally indexing said sprocket to correspondingly position another cartridge of said cartridge belt along said second line of travel.