A rotary ammunition magazine cooperates with a bolt catch to hold the bolt of a firearm out of battery in an open position after the last round has been fired. A cam mounted on the rotor of the magazine actuates a movable body on the magazine housing as the cam rotates to feed ammunition to the action. The body moves to an extended position and engages a bolt catch pivotably mounted in the firearm receiver. The bolt catch is pivoted by the body into a position where it will engage the bolt and prevent it from returning to battery after the last round has been fired.

A lower receiver assembly of a rifle including a lower receiver having a magazine well formed thereon between a distal end and a proximal end, the lower receiver operable to receive a trigger assembly including a trigger, a hammer, and a firing pin. The lower receiver can include an operating rod retention tab coupled with an upper surface of the receiver and the operating rod retention tab extends above the upper surface and is operable to be received in a groove formed in a receiver of an upper receiver.

An auto-releasing method and arrangement of a detachable magazine for a firearm is provided. The auto-releasing arrangement is able to physically remind the operator that it is the right time to replace the magazine and to continue fire without having to performing a series of magazine reloading operations to reset the firearm into the fire mode, wherein the magazine will automatically be released and removed from the magazine receiving cavity of the firearm. In other words, the operator can simply insert another loaded magazine into the magazine receiving cavity while the firearm still has at least one cartridge chambered for firing, so that the time cost on performing such operations can substantially be saved to increase the survival probability during a gunfight or the like.

An auto-releasing method and arrangement of a detachable magazine for a firearm is provided. The auto-releasing arrangement is able to physically remind the operator that it is the right time to replace the magazine and to continue fire without having to performing a series of magazine reloading operations to reset the firearm into the fire mode, wherein the magazine will automatically be released and removed from the magazine receiving cavity of the firearm. In other words, the operator can simply insert another loaded magazine into the magazine receiving cavity while the firearm still has at least one cartridge chambered for firing, so that the time cost on performing such operations can substantially be saved to increase the survival probability during a gunfight or the like.

A firearm comprising: (i) an ammunition magazine which automatically ejects from the lower receiver of the firearm when the ammunition magazine is spent; (ii) a control group comprising a magazine release mechanism for releasing the magazine catch so that the ammunition magazine is detachable from the lower receiver, a bolt catch engage mechanism for engaging the bolt catch with the bolt carrier and retaining the bolt carrier in the retracted position, and a bolt catch release mechanism for releasing the bolt catch from the bolt carrier and allowing the bolt carrier to move forward, wherein the control group components can be operated by the user on either the left side or right side of the firearm; and (iii) optionally, a charging handle which can be operated by the user on either the left side or right side of the firearm.

A firearm comprising: (i) an ammunition magazine which automatically ejects from the lower receiver of the firearm when the ammunition magazine is spent; (ii) a control group comprising a magazine release mechanism for releasing the magazine catch so that the ammunition magazine is detachable from the lower receiver, a bolt catch engage mechanism for engaging the bolt catch with the bolt carrier and retaining the bolt carrier in the retracted position, and a bolt catch release mechanism for releasing the bolt catch from the bolt carrier and allowing the bolt carrier to move forward, wherein the control group components can be operated by the user on either the left side or right side of the firearm; and (iii) optionally, a charging handle which can be operated by the user on either the left side or right side of the firearm.

A bolt stop actuator is disclosed. The actuator may include a lift arm, a first leg extending from a point proximate to an end of the lift bar and generally perpendicular therefrom, a second leg extending in the same direction from the lift bar as the first leg, and a projection extending from the lift bar and configured to contact a follower of an empty magazine when the bolt stop actuator is assembled into a firearm. Neither the first leg, nor the second leg, include apertures positioned distal to the lift arm.

A bolt stop actuator is disclosed. The actuator may include a lift arm, a first leg extending from a point proximate to an end of the lift bar and generally perpendicular therefrom, a second leg extending in the same direction from the lift bar as the first leg, and a projection extending from the lift bar and configured to contact a follower of an empty magazine when the bolt stop actuator is assembled into a firearm. Neither the first leg, nor the second leg, include apertures positioned distal to the lift arm.

A firearm receiver assembly includes a receiver body, a threaded mount at a rear portion of the receiver body, a magazine release assembly including a magazine release portion on at least one side of the receiver body, a bolt release assembly including a bolt release central portion and a bolt release portion on at least one side of the receiver body, and a safety selector assembly including a safety portion on at least one side of the receiver body. The bolt release central portion translates vertically within a cavity of the receiver body.

Provided is a fast cycling/low recoil pistol caliber carbine assembly. The carbine assembly may include an upper receiver, a lower receiver, a feed ramp, a bolt stop, a magazine, a control mechanism comprising a control lever, a control base, a control pivot pin, and a control spring, an ejector, a gap filler member. The assembly provides last round bolt hold open, trigger finger actuated bolt release, short stroke cycle, barrel ramp, ambidextrous magazine release, and uses Glock magazines.