Embodiments of the invention are directed to enhancing insensitive munitions performance. Some embodiments of the invention employ an outgassing pad having unique geometrical configurations and positioning. Other embodiments rely on using thermally-releasable components to foster billet expulsion. Additional embodiments combine both aspects into an entire cook-off mitigation system.

Embodiments of the invention are directed to enhancing insensitive munitions performance. Some embodiments of the invention employ an outgassing pad having unique geometrical configurations and positioning. Other embodiments rely on using thermally-releasable components to foster billet expulsion. Additional embodiments combine both aspects into an entire cook-off mitigation system.

A weapon having a barrel cluster, having at least one, preferably multiple, weapon barrel(s) and comprising a bolt, wherein only one of the weapon barrels is oriented in alignment with the single bolt and interacts therewith for the purposes of firing. The barrel cluster has a front, muzzle-side barrel holder and has a rear, bolt-side barrel holder, and has, in a partial region, a control body with a control cam which is incorporated on the circumference. By way of said control cam, the barrel cluster can be adjusted as a whole and independently of the firing of the weapon. The control body is preferably electronically rotated, for which purpose a pin of the actuaor engages into the control cam of the control body.

A selective fire firearm may be provided having a fully automatic open bolt and a semi-automatic closed bolt mode of operation. The firearm may include a trigger group having a trigger prop that ensures that, when the trigger is released in the fully automatic open bolt mode, the bolt carrier stops in an open bolt position held by an open bolt sear. The trigger prop may include a foot that, following a first trigger pull in the fully automatic open bolt mode, slides under and props a rear end of the trigger in a position that allows the open bolt sear to catch the bolt carrier when the trigger is released and propped but prevents the trigger sear from engaging the hammer.

A semi-automatic rifle is configured to fire single rounds of ammunition via a magazine or a belt of ammunition. A receiver cover pivots open to receive the first round of a belt of ammunition or a magazine can be inserted in a magazine well. The rifle operates using a closed bolt firing cycle, with a sliding hammer that, on its return from recoil after firing a first round, is caught by a sear regardless of whether the trigger is still in the pulled position. The trigger must be fully released before a second round can be fired.