Abstract: A fixed magazine for a rifle has a projecting boss within the magazine well that engages a cavity in the magazine. Once the magazine is inserted and the boss engages the cavity, the magazine is fixed and may not be removed from the rifle. The magazine is loaded by separating the upper receiver from the lower receiver and exposing the magazine opening, allowing it to receive rounds of ammunition.

Abstract: A revolver has a spring biased rod that extends from the cylinder, the rod having a tip that engages a portion of the frame to retain the cylinder within the aperture of the frame during firing. The rod is movable out of engagement with the frame portion to release the cylinder and allow it to pivot on a yoke for ejection of spent shells and reloading. A pin is mounted in the yoke so as to engage a recess in the frame when the cylinder is within the aperture of the frame. The pin retains the cylinder within the aperture and is spring loaded and movable out of engagement with the recess to permit the cylinder to pivot on the yoke for ejection of spent shells and reloading.

Abstract: A barrel for a semiautomatic firearm operating under the short recoil system has one or more cam followers projecting outwardly to engage one or more cams positioned on an inner surface of a slide surrounding the barrel. Interaction between the cams and the cam followers controls the angle between the longitudinal axis of the barrel and the axis of motion of the slide to prevent the breech end of the barrel from moving too far as the barrel tilts as it unlocks from the slide, ensuring that the extractor will engage the rim of a spent casing and extract it from the chamber during recoil.

Abstract: An improved muzzle-loading firearm with a removable, threadless breech plug retained by a breech plug retaining collar, and a barrel retaining nut for simplifying manufacture, cleaning, preventing fouling and over-pressure situations, and minimizing alignment issues during assembly of the firearm. The removable, threadless breech plug also allows for straightforward interchangeability of breech plugs for use with various primers and propellants. The muzzle-loading firearm has a barrel with a protrusion on the breech end of the barrel that fits into a matched groove within the mono block for use in aligning the barrel during assembly of the firearm. The muzzle-loading firearm has a barrel retaining nut, wherein the barrel retaining nut is internally threaded to accept the threaded end of the barrel thereby retaining the barrel in the mono block.

Abstract: To prevent inertial forces from inadvertently releasing the slide of a semi-automatic pistol into battery, a slide stop retention mechanism is mounted on the frame. A finger extends from the mechanism and pivots under the force of a biasing spring into engagement with the slide stop when the slide is in the open position. The finger supports the slide stop. A force applied to the slide stop, either manually or via a cam on the slide when the slide is pulled back and released, will move the finger out of its supporting position and allow the slide to move to battery.

Abstract: A barrel for a semiautomatic firearm operating under the short recoil system has one or more cam followers projecting outwardly to engage one or more cams positioned on an inner surface of a slide surrounding the barrel. Interaction between the cams and the cam followers controls the angle between the longitudinal axis of the barrel and the axis of motion of the slide to prevent the breech end of the barrel from moving too far as the barrel tilts as it unlocks from the slide, ensuring that the extractor will engage the rim of a spent casing and extract it from the chamber during recoil.

Abstract: A fixed magazine for a rifle has a projecting boss that engages a cavity within the magazine well of the rifle. Once the magazine is inserted and the boss engages the cavity, the magazine is fixed and may not be removed from the rifle. The magazine is loaded by separating the upper receiver from the lower receiver and exposing the magazine opening, allowing it to receive rounds of ammunition.

Abstract: An adjustable gas block is used to regulate the flow rate of gas from a barrel to an action in a gas-operated firearm. The adjustable gas block uses a movable body with an opening having a width and length, the width of the opening varying in size as a function of its length. The movable body is transversely positioned relative to a conduit between the barrel and the action, such that movement of the body and its opening relative to the conduit serves to regulate the flow rate of gas between the barrel and the action.

Abstract: A magazine for a firearm is formed by a plurality of sidewalls that define a space for holding ammunition cartridges. An opening between two of the walls provides access to the space. Feed lips are positioned on opposite sides of the opening. The feed lips contact and retain the cartridges within the space. Feed ramp surfaces are positioned on opposite sides of the opening. The feed ramp surfaces are angularly oriented to tilt a cartridge so that it may be fed into the chamber of a barrel as it is pushed out of the opening along the feed ramp surfaces. Guide surfaces are positioned on opposite sides of the opening between the feed lips and the feed ramp surfaces. The guide surfaces guide the cartridge as it disengages from the feed lips and moves up along the feed ramp surfaces.

Abstract: To prevent inertial forces from inadvertently releasing the slide of a semi-automatic pistol into battery, a slide stop retention mechanism is mounted on the frame. A finger extends from the mechanism and pivots under the force of a biasing spring into engagement with the slide stop when the slide is in the open position. The finger supports the slide stop. A force applied to the slide stop, either manually or via a cam on the slide when the slide is pulled back and released, will move the finger out of its supporting position and allow the slide to move to battery.

Abstract: A catch is used to secure upper and lower receiver portions of a modern sporting rifle to one another. The catch may be mounted in either receiver portion and includes a shaft on which a body is mounted. The body has a hook and a cam follower positioned on opposite sides of the shaft. The cam follower engages a cam surface, which rotates the hook into engagement with a contact surface to secure the receiver portions to one another when they are pivoted into a closed configuration.

Abstract: A receiver assembly includes a bolt, a receiver having a threaded portion receiving a barrel, a barrel having a threaded portion engaged with the threaded portion of the receiver, and a crush washer positioned over the threaded portions between the barrel and the receiver to permit adjustment of the barrel relative to the receiver to achieve a proper headspacing.

Abstract: Several improvements to the components and assembly method of a bolt-action firearm are disclosed. An improved bolt includes two separate members, which makes the bolt less expensive to manufacture while having a stronger extension handle. An improved takedown system and buttonless stop provide two easy ways to remove a bolt from a receiver when desired without misplacing any parts. An improved scope mount has a base connected to a receiver with two ends that substantially cover the top surface of the receiver and a middle portion that is narrowed over an opening to the receiver to accommodate a cartridge. A method of assembling a firearm involves providing a barrel with a threaded portion, fitting a crush washer over the threaded portion, inserting the threaded portion into a corresponding threaded portion of a receiver, and adjusting the barrel about the crush washer until a proper headspace is achieved.

Abstract: A pistol has a disconnector for disconnecting a trigger bar from a sear to allow the sear to reset and engage and hold a hammer in a cocked position. Motion of a slide causes rotation of the disconnector through interaction between a cam surface on the slide and a cam follower on the disconnector. A contact surface on the disconnector engages the trigger bar upon rotation of the disconnector and moves the trigger bar out of engagement with the sear. A biasing spring resets the sear into engagement with the hammer which is rotated into the cocked position by motion of the slide.

Abstract: An action lock for a Modern Sporting Rifle pump action firearm is pivotably mounted within the lower receiver of the rifle and has a stop surface that engages a contact surface on the bolt carrier when the bolt carrier is in battery. A cam on the hammer or the trigger engages a cam surface on the action lock when the hammer is released by a pull of the trigger. Cam action rotates the action lock out of engagement with the bolt carrier, unlocking it and allowing the fore end grip to be pumped to cycle the action and extract and eject the spent casing and strip and chamber a new round.

Abstract: An action lock for a Modern Sporting Rifle pump action firearm is pivotably mounted within the lower receiver of the rifle and has a stop surface that engages a contact surface on the bolt carrier when the bolt carrier is in battery. A cam on the hammer or the trigger engages a cam surface on the action lock when the hammer is released by a pull of the trigger. Cam action rotates the action lock out of engagement with the bolt carrier, unlocking it and allowing the fore end grip to be pumped to cycle the action and extract and eject the spent casing and strip and chamber a new round.

Abstract: A firearm includes a frame having at least one interior receptacle defined by opposed interior walls and having opposed guide rails extending from the opposed interior walls, and at least one modular housing disposed in the receptacle and accommodating at least one operational component of the firearm. The modular housing is defined by opposed sidewalls having opposed guide channels formed therein, the guide channels being configured to selectively engage the guide rails to facilitate the aligning of the modular housing with respect to the interior receptacle. The at least one operational component and the modular housing are pre-assembled together as an integrated unit for drop-in insertion into the receptacle during assembly of the firearm.