An improvement is made in an externally driven gun having an ammunition feeder capable of providing at least two types of ammunition to the gun by incorporating a gear transmission into the driving mechanism coupled to the ammunition feeder to appropriately control an in-feed sprocket within the ammunition feeder so that the ammunition type can be changed prior to commitment of the previously selected type of ammunition to the firing mechanism of the gun. The gear transmission which is coupled to the in-feed sprocket provides acceleration to the sprocket at the last possible moment prior to handing-off the round to the firing mechanism. In one embodiment the gear transmission includes a cam follower rotatably coupled about an offset axis to the input shaft and coupled to the output shaft through a radial slot. The cam follower is rotated by means of a stationary cam race as the follower itself is rotated as a whole by the input shaft. The output shaft is coupled to the cam follower by a pin extending into the radial slot. In a second embodiment, the gear transmission includes a planet gear rotatably coupled to the input shaft about an offset axis and engaging a stationary ring gear. A slider is provided about an offset axis on the planet gear and engages a radially defined slot in the output shaft. Both embodiments convert a substantially uniform angular velocity into an oscillating angular velocity to effect the desired acceleration of the in-feed sprocket.

An ammunition storage and retrieval system for a weapon is provided. The storage and retrieval system includes a main magazine having a main carrier belt that is configured to store a plurality of munitions have a first set of handling characteristics and a handoff unit that retrieves a selected one of the plurality of munitions and transfers the selected munition to the weapon. The main magazine also includes an auxiliary magazine mount. There is further provided a set of auxiliary magazines that are selectively engageable with the auxiliary magazine mount. A first one of the auxiliary magazines is configured to store munitions having the first set of handling characteristics and a second one of the auxiliary magazines is configured to store munitions having a second set of handling characteristics.

The side stripping of ammunition from linked ammunition belts in an automatic weapon system is improved by providing a stripping mechanism including a link sprocket for engaging the link belt and rounds and including a synchronously rotating follower guide. A plurality of followers are disposed and slidable within a corresponding plurality of radial slots defined in the follower guide. Two followers are provided for each round which could be accommodated by the link sprocket. The follower slides radially along the slot in the following guide toward and away from its corresponding round as controlled by a cam pin extending from the follower and engaging a cam raceway in an adjacent fixed cam plate. By this means a purely radially force is symmetrically applied to each round through the longitudinal axis of the round and perpendicular to the axis of the sprocket so that no net torque is applied to the round or its corresponding link. Furthermore, the sprocket size and rate of rotation is chosen so that the tangential velocity at handoff of the round to a feed rotor from the link sprocket substantially equals the tangential velocity imparted to the round by the feed rotor which accepts the stripped round and carries the round into a feed mechanism within the automatic weapon system.

This invention provides for a feeder tray which is journaled for rotation on a longitudinal axis and which includes two longitudinally extending cutouts, one for receiving fresh rounds of ammunition in sequence from a constant velocity train of ammunition and for transferring each round to the face of the gun bolt in aft dwell, the other for receiving the fired case and for displacing the fired case from the face of the gun bolt, and driven by a cylindrical cam system.

An improved double-feed arrangement for introducing munition shells into the breech of an automatic weapon such as a machine gun. The double-feed arrangement includes a housing having two munition belt inlet openings and two munition belt outlet openings respectively equidistantly disposed from the longitudinal axis of the automatic weapon. A pair of hollow transport shafts rotatable in said housing and adapted to be selectively driven by a driving mechanism which can be energized by the recoil of the automatic weapon. A sprocket wheel having a plurality of equidistantly spaced shell receiving seats is mounted on each hollow transport shaft. The sprocket wheels are adapted to normally rotate in mutually opposite directions in a stepwise manner except when a selective switching from one feed to the other feed if effected, whereby a rotational step is imparted on both feeds by the driving mechanism via switching mechanisms to effect a rotation in the same direction. The shell of a first type is then moved from a firing chamber introducing position to a waiting position while the shells of a second type are now stepwise fed into the firing chamber introducing position by the other feed.