Abstract: An adjustable insert for a firearm magazine can include: a contact surface to contact a cartridge shoulder; and an engagement interface positioned on a mating surface, the engagement interface being engageable with a portion of the firearm magazine, wherein the mating surface is positioned perpendicular to the contact surface; and wherein the engagement interface includes a predetermined adjustment resolution for incrementally adjusting the adjustable insert forward and backward along a plane parallel to a longitudinal axis of the firearm magazine to accommodate multiple sizes of cartridges.

Abstract: A firearm can include a receiver, a bolt, and a gas block. In certain implementations, the receiver and/or barrel extension includes a locking shoulder, a lug-interface region forward of the locking shoulder, and a channel wall that defines a bolt channel and a bolt-lug raceway rearward of the locking shoulder. In some implementations, the bolt includes a bolt lug. The bolt lug can be sized and shaped to slidably engage the bolt-lug raceway. Additionally, the bolt can be positioned within the bolt channel of the receiver. Further, the gas block can be positioned at the lug-interface region. In some implementations, the gas block is rotatable with the bolt lug. In particular implementations, the gas block includes a raceway plug sized and shaped to block the bolt-lug raceway. The gas block can also include a bolt-lug notch sized and shaped to mate with the bolt lug.

Abstract: Embodiments of the present disclosure relate to trigger mechanisms for firearms. In one aspect of the present disclosure, the trigger mechanism can include a linkage between a striker sear and a main sear to control an amount of force exerted on the main sear by the striker sear. A portion of the force exerted on the striker sear by the striker can be exerted on the main sear through the sear linkage. In another aspect of the present disclosure, trigger mechanisms are described which additionally, or alternatively utilize one or more biasing members to provide a variable trigger pull weight.

Abstract: Embodiments of the present disclosure relate to trigger mechanisms for firearms. In one aspect of the present disclosure, the trigger mechanism can include a linkage between a striker sear and a main sear to control an amount of force exerted on the main sear by the striker sear. A portion of the force exerted on the striker sear by the striker can be exerted on the main sear through the sear linkage. In another aspect of the present disclosure, trigger mechanisms are described which additionally, or alternatively utilize one or more biasing members to provide a variable trigger pull weight.

Abstract: A number of embodiments of a firearm are disclosed where the firearm includes a magazine configured to hold the bolt in an open position when the magazine is empty. In one embodiment, the firearm includes a bolt stop mechanism that moves between a first position where it allows the bolt to cycle between an open position and a closed position and a second position where it holds the bolt in the open position. The magazine is configured to actuate the bolt stop mechanism to the first position when the magazine is empty.

Abstract: A number of embodiments of a firearm are disclosed where the firearm includes a magazine configured to hold the bolt in an open position when the magazine is empty. In one embodiment, the firearm includes a bolt stop mechanism that moves between a first position where it allows the bolt to cycle between an open position and a closed position and a second position where it holds the bolt in the open position. The magazine is configured to actuate the bolt stop mechanism to the first position when the magazine is empty.

Abstract: A number of embodiments of a firearm are disclosed where the firearm includes a magazine configured to hold the bolt in an open position when the magazine is empty. In one embodiment, the firearm includes a bolt stop mechanism that moves between a first position where it allows the bolt to cycle between an open position and a closed position and a second position where it holds the bolt in the open position. The magazine is configured to actuate the bolt stop mechanism to the first position when the magazine is empty.

Abstract: A number of embodiments of a firearm are disclosed where the firearm includes a magazine configured to hold the bolt in an open position when the magazine is empty. In one embodiment, the firearm includes a bolt stop mechanism that moves between a first position where it allows the bolt to cycle between an open position and a closed position and a second position where it holds the bolt in the open position. The magazine is configured to actuate the bolt stop mechanism to the first position when the magazine is empty.

Abstract: A number of embodiments of a firearm are disclosed where the firearm includes a magazine configured to hold the bolt in an open position when the magazine is empty. In one embodiment, the firearm includes a bolt stop mechanism that moves between a first position where it allows the bolt to cycle between an open position and a closed position and a second position where it holds the bolt in the open position. The magazine is configured to actuate the bolt stop mechanism to the first position when the magazine is empty.

Abstract: Outerwear, such as thermally insulated jackets and pants are disclosed. The outerwear may include insulative panels that are positioned, oriented, sized, and shaped according to a body mapping. The body mapping may indicate areas where insulative material should be reduced to improve the mobility of a wearer of the outerwear.

Abstract: A resetting magazine cut-off control system for a firearm includes a magazine and a control cuff that has a cuff cam surface and a cuff stop surface and is operable between a first position and a second position relative to the magazine. The system also includes an action member having a first portion and a second portion, with the second portion having an action stop surface. Contact between the cuff stop surface and the action stop surface prevents longitudinal movement of the action member when the control cuff is in the first position, and the first portion applies a force to the cuff cam surface, with the force moving the control cuff from the first to the second position, when the action stop surface is moved away from the cuff stop surface. The system allows a shooter to automatically switch between shooting modes by using the firearm's action.

Abstract: A number of embodiments of a firearm are disclosed where the firearm includes a magazine configured to hold the bolt in an open position when the magazine is empty. In one embodiment, the firearm includes a bolt stop mechanism that moves between a first position where it allows the bolt to cycle between an open position and a closed position and a second position where it holds the bolt in the open position. The magazine is configured to actuate the bolt stop mechanism to the first position when the magazine is empty.

Abstract: Outerwear, such as thermally insulated jackets and pants are disclosed. The outerwear may include insulative panels that are positioned, oriented, sized, and shaped according to a body mapping. The body mapping may indicate areas where insulative material should be reduced to improve the mobility of a wearer of the outerwear.

Abstract: Composite recoil-absorbing stocks for firearms are disclosed. One stock has a rigid body that has an internal cavity. A compressible insert may be positioned in the rigid body with an elongated front end that is narrower than a broadened rear end. The front end is positioned in a narrowed front end of the internal cavity, and the rear end is positioned in a wider rear end of the cavity. When the firearm recoils, the compressible insert can be positioned between the shooter and the rest of the firearm and can therefore dampen and absorb recoil forces. The positioning and size of the rigid body and compressible insert help prevent bending and buckling of the compressible insert, thereby limiting the effect that the compression of the insert has on aiming and accuracy of the shot. Other embodiments and related methods are also disclosed.

Abstract: Knives configured to use interchangeable blades, blades for those knives, and methods of making an using the knives and blades are disclosed. One knife includes a latch assembly that retains a blade in a slot of the latch assembly using a dual-stage locking mechanism wherein two different latches must be operated to exchange the blade in the slot. One latch is a button that translates a pin through the slot, and the other latch is a rocker lever that rotates into and out of contact with a notch, recess, or groove in the blade. The first latch controls movement of the second latch in order to help avoid inadvertent removal or dislodgement of the blade. Some blades include multiple notches or recesses so that they provide multiple points of contact that resist translation and rotation of the blade out of the slot, even when subjected to unusually-directed forces.

Abstract: A firearm choke tube includes a cylindrical body, a choke interrupted thread section, and a locking tab. The choke interrupted thread section is positioned on an outer surface of the cylindrical body and configured to threadably engage an interrupted thread section of a barrel of a firearm to limit longitudinal movement of the cylindrical body relative to the barrel. The locking tab protrudes from the outer surface of the cylindrical body and is configured to interface with a detent formed in the barrel to limit rotational movement of the cylindrical body relative to the barrel.

Abstract: Firearm comprising a receiver (2); a barrel (6) mounted with one end on the receiver (2); a breech (8) equipped with a loading lever (9) mounted, in a way so that it can slide, in the receiver (2); at least one return spring (15) to return the breech (8) to its closed position, characterized in that the return spring (15) is a tension spring of the ‘constant-force’ type that is mounted between the breech (8) and a fixed support (12) with respect to the receiver and the barrel.