Abstract: An optic guard for a firearm may include: a frame; and a bracket having a first side to attach to a firearm assembly, the bracket integrally formed with the frame or fixably attached to the frame at a second side of the bracket. The frame may be arranged to protect a top and sides of the optic when the first side of the bracket is attached to the firearm assembly. In some embodiments, the second side of the bracket defines an optic attachment, wherein the frame protects the top and sides of the optic when the optic is coupled to the bracket using the optic attachment. In some embodiments, the first side of the bracket may define a protrusion or opening to mate with an opening or protrusion in front of an optic mounting platform.

Abstract: Methods and systems for low etch pit density 6 inch semi-insulating gallium arsenide wafers may include a semi-insulating gallium arsenide single crystal wafer having a diameter of 6 inches or greater without intentional dopants for reducing dislocation density, an etch pit density of less than 1000 cm?2, and a resistivity of 1×107 ?-cm or more. The wafer may have an optical absorption of less than 5 cm?1 less than 4 cm?1 or less than 3 cm?1 at 940 nm wavelength. The wafer may have a carrier mobility of 3000 cm2/V-sec or higher. The wafer may have a thickness of 500 ?m or greater. Electronic devices may be formed on a first surface of the wafer. The wafer may have a carrier concentration of 1.1×107 cm?3 or less.

Abstract: Methods and wafers for low etch pit density, low slip line density, and low strain indium phosphide are disclosed and may include an indium phosphide single crystal wafer having a diameter of 4 inches or greater, having a measured etch pit density of less than 500 cm?2, and having fewer than 5 dislocations or slip lines as measured by x-ray diffraction imaging. The wafer may have a measured etch pit density of 200 cm?2 or less, or 100 cm?2 or less, or 10 cm?2 or less. The wafer may have a diameter of 6 inches or greater. An area of the wafer with a measured etch pit density of zero may at least 80% of the total area of the surface. An area of the wafer with a measured etch pit density of zero may be at least 90% of the total area of the surface.

Abstract: In various embodiments, an apparatus may include a frame to protect a front-most light transmissive surface of an optic sight or framing thereof, wherein a part of a back of the frame is spaced apart from the front-most light transmissive surface of the optic sight or the framing thereof; wherein the frame is integrally formed on a front of the optic sight or configured to fixably or releasably coupled to the front of the optic sight, or wherein the frame is configured to fixably or releasably attach to an optic mounting plate or other optic mounting adapter on which the optic sight is mountable, and wherein in the case the frame is configured to fixably or releasably attach to the optic mounting plate or other optic mounting adapter, the frame includes an attachment interface to interference fit, via press-fit or mechanical deformation, to the optic mounting plate or other optic mounting adapter. Other embodiments may be disclosed and/or claimed.

Abstract: In various embodiments, an optic sight or an apparatus usable with an optic sight may include a protective flexing member, and/or a mechanical rear sight or a representation thereof viewable when looking through the optic sight when the optic sight is mounted to a firearm assembly; wherein: the mechanical rear sight or the representation thereof is integrally formed with the optic sight, and a rearmost part of the rear mechanical sight is positioned in front of the emitter of the optic sight, or the mechanical rear sight comprises a modular mechanical rear sight to fit into a slot or other opening of the firearm assembly or the optic sight, and a rearmost part of the rear mechanical sight is positioned in front of a front-most light transmissive surface of the optic sight. Other embodiments may be disclosed and/or claimed.

Abstract: Some embodiments may include a firearm or a firearm retrofit assembly including a compensation system to reduce recoil, the compensation system operable with a barrel that includes 1) a muzzle and 2) at least one egress in a length of the barrel, the compensation system to redirect gas expelled from the at least one egress in the length of the barrel. Other embodiments may be disclosed and/or claimed.

Abstract: A gas block assembly may include a gas block including a gas port to receive gas provided by a gas port of a barrel; a tapered fastener opening; and a tapered fastener insertable in the tapered fastener opening, the tapered fastener including: a length further including a tapered section to contact a sidewall that defines the tapered fastener opening; and means for rotationally driving the tapered fastener into the tapered fastener opening. In other embodiments, an adjustable gas block includes sealing ring(s) on a groove in a rotationally actuated gas metering shaft.

Abstract: In various embodiments, an apparatus is provided, the apparatus comprising: a foldable opposable grip assembly to couple to a firearm, the foldable opposable grip assembly including: an opposable grip device movably attachable to a mount that is attachable to, or integrated with, the firearm, to foldup the opposable grip assembly; and a surface grippable using a thumb of a support hand when the foldable opposable grip assembly is coupled to the firearm and unfolded. Other embodiments may be disclosed and/or claimed.

Abstract: In various embodiments, an apparatus is provided, the apparatus comprising an assembly an assembly to operate in a recoil environment in which the assembly is mounted on a device that produces or transmits recoil; wherein at least one part of the assembly is self-lockingly fastened to a mating part, the mating part comprising another part of the assembly, a reciprocating part of a recoil-producing device, or another part of the recoil-producing device; the self-lockingly fastened parts including a threaded opening, and a non-threaded opening over the threaded opening, the non-threaded opening defining: a tapered opening to form a locking taper, or a tapered counter opening arranged to make taper-to-taper contact with a corresponding taper defined by a rotatably-driven part, wherein the threaded hole is arranged to mate with threading defined by the rotatably-driven part. Other embodiments may be disclosed and/or claimed.

Abstract: In various embodiments, an optic assembly mount arranged to receive an optic or a bracket on which the optic is installed, wherein optic assembly mount includes: a first undercut; and wherein an underside of the bracket includes a second undercut to mate with the first undercut; wherein the apparatus further comprises a rotatably driven fastener including a head to forwardly urge the bracket relative to the locating optic assembly mount to interlock the undercuts. Other embodiments may be disclosed and/or claimed.

Abstract: In various embodiments, an apparatus comprises a locating optic assembly mount arranged to receive an optic or a bracket on which the optic is installed, wherein the locating optic assembly mount includes: one or more locating fastener openings to receive one or more locating fasteners with threaded sections and non-threaded shoulders, wherein the non-threaded shoulders extend through the optic or bracket and below a surface located below the optic or bracket, each locating fastener opening including: a threaded hole to mate with the threaded section of the corresponding locating fastener; and a counter opening located above the threaded hole, wherein the counter opening is arranged to slip fit with the non-threaded shoulder of the corresponding locating fastener to align a center axis of the locating fastener with a center axis of the locating fastener openings. Other embodiments may be disclosed and/or claimed.

Abstract: A firearm or a firearm retrofit assembly to provide the firearm with gas compensation to reduce recoil, wherein a barrel of the firearm or firearm retrofit assembly includes a length having an egress for gas propelled from a chamber inside the barrel, the firearm or a firearm retrofit assembly includes a compensation device to mount in front or behind a front wall of a slide associated with the barrel, the compensation device including: a first side having an opening arranged to fit around a length of the barrel; and a second different side having an opening to expose the egress of the length of the bore.

Abstract: Some embodiments may include a firearm magazine base pad assembly or magazine extension assembly comprising a top, a bottom, and a cavity between the top and bottom, the cavity for a core or removable insert, the firearm magazine base pad assembly or magazine extension assembly further comprising: means for slidingly receiving a bottom of a magazine, the slidingly receiving means including a channel to receive a lip defined by the bottom of the magazine and tab slots to mate with tabs above the lip; and the core or removable insert located in the cavity. Other embodiments may be disclosed and/or claimed.

Abstract: An optic guard for a firearm may include: a frame; and a bracket having a first side to attach to a firearm assembly, the bracket integrally formed with the frame or fixably attached to the frame at a second side of the bracket. The frame may be arranged to protect a top and sides of the optic when the first side of the bracket is attached to the firearm assembly. In some embodiments, the second side of the bracket defines an optic attachment, wherein the frame protects the top and sides of the optic when the optic is coupled to the bracket using the optic attachment. In some embodiments, the first side of the bracket may define a protrusion or opening to mate with an opening or protrusion in front of an optic mounting platform.

Abstract: In some embodiments, a tunable recoil assembly is provided. The tunable recoil assembly may include a guide rod having a front end, a length, and a rear end; one or more springs around the length of the guide rod; and a removable cap releasably coupled to one of the ends of the guide rod. In some embodiments, the removable cap may be retained using a spring force, and may be slidingly coupled, twistingly coupled, or otherwise releasably coupled to the one of the ends of the guide rod.

Abstract: Methods and systems for low etch pit density 6 inch semi-insulating gallium arsenide wafers may include a semi-insulating gallium arsenide single crystal wafer having a diameter of 6 inches or greater without intentional dopants for reducing dislocation density, an etch pit density of less than 1000 cm?2, and a resistivity of 1×107 ?-cm or more. The wafer may have an optical absorption of less than 5 cm?1 less than 4 cm?1 or less than 3 cm?1 at 940 nm wavelength. The wafer may have a carrier mobility of 3000 cm2/V-sec or higher. The wafer may have a thickness of 500 ?m or greater. Electronic devices may be formed on a first surface of the wafer. The wafer may have a carrier concentration of 1.1×107 cm?3 or less.

Abstract: A firearm or firearm retrofit assembly may include a compensation assembly to receive gas expelled from a muzzle of a barrel or an egress in a length of the barrel. The compensation assembly may include one or more gas flow-directing sections to tune the flow of gas through the compensation assembly, which may reduce recoil. Other embodiments may be disclosed and/or claimed.

Abstract: Methods and wafers for low etch pit density, low slip line density, and low strain indium phosphide are disclosed and may include an indium phosphide single crystal wafer having a diameter of 4 inches or greater, having a measured etch pit density of less than 500 cm?2, and having fewer than 5 dislocations or slip lines as measured by x-ray diffraction imaging. The wafer may have a measured etch pit density of 200 cm?2 or less, or 100 cm?2 or less, or 10 cm?2 or less. The wafer may have a diameter of 6 inches or greater. An area of the wafer with a measured etch pit density of zero may at least 80% of the total area of the surface. An area of the wafer with a measured etch pit density of zero may be at least 90% of the total area of the surface.

Abstract: Some embodiments include an optic guard for a firearm, the optic guard including: a frame; and a bracket having a side to attach to a firearm assembly, the bracket integrally formed with the frame or fixably attached to the frame; wherein the frame is arranged to cover part of a front of an optic housing when the side of the bracket is attached to the firearm assembly. Other embodiments may be disclosed and/or claimed.

Abstract: An adapter assembly for mounting an optic on a firearm using nuts mountable on bolts, threaded studs, or threaded posts is provided. The adapter assembly may include a bracket having a bottom section to mount to a firearm assembly, and a top side to receive the optic; wherein the threaded posts are integrally formed on the top side of the bracket, or wherein the bracket includes: pockets arranged to mate with at least part of heads of the bolts or studs, the pockets on a bottom side of the bracket; and through openings to receive shanks of the bolts or a different part of the heads of the bolts, or shanks of the studs. Other embodiments may be disclosed and/or claimed.