Abstract: Apparatuses, systems, and methods comprising acoustically absorptive air ducts comprising an internally positioned structure component as an endoskeleton and an air impervious inner layer, and an acoustically absorptive foam outer layer, environmental control systems comprising such air ducts, and vehicles incorporating such environmental control systems are disclosed with methods for manufacture and installations are disclosed.

Abstract: A trigger assembly for a firearm is disclosed wherein the firearm includes a receiver, a safety selector and a hammer. The trigger assembly includes a trigger having a pivot axis, a front hook which is constructed and arranged to move with trigger rotation, a rear hook which is cooperatively arranged with the front hook and a spring which is positioned between the front hook and the rear hook. The front hook and the trigger are constructed and arranged relative to the safety selector and relative to the hammer in order to allow the hammer to be recocked from an upright position with the safety selector in a “SAFE” position. This particular construction provides a trigger assembly which is constructed and arranged as a two-stage, drop-in trigger assembly which is compliant with the European Standard for an M4/M16 (AR) platform.

Abstract: A trigger assembly for a firearm is disclosed wherein the firearm includes a receiver, a safety selector and a hammer. The trigger assembly includes a trigger having a pivot axis, a front hook which is constructed and arranged to move with trigger rotation, a rear hook which is cooperatively arranged with the front hook and a spring which is positioned between the front hook and the rear hook. The front hook and the trigger are constructed and arranged relative to the safety selector and relative to the hammer in order to allow the hammer to be recocked from an upright position with the safety selector in a “SAFE” position. This particular construction provides a trigger assembly which is constructed and arranged as a two-stage, drop-in trigger assembly which is compliant with the European Standard for an M4/M16 (AR) platform.

Abstract: A trigger assembly for a firearm is disclosed wherein the firearm includes a receiver, a safety selector and a hammer. The trigger assembly includes a trigger having a pivot axis, a front hook which is constructed and arranged to move with trigger rotation, a rear hook which is cooperatively arranged with the front hook and a spring which is positioned between the front hook and the rear hook. The front hook and the trigger are constructed and arranged relative to the safety selector and relative to the hammer in order to allow the hammer to be recocked from an upright position with the safety selector in a “SAFE” position. This particular construction provides a trigger assembly which is constructed and arranged as a two-stage, drop-in trigger assembly which is compliant with the European Standard for an M4/M16 (AR) platform.

Abstract: A trigger assembly for a firearm is disclosed wherein the firearm includes a receiver, a safety selector and a hammer. The trigger assembly includes a trigger having a pivot axis, a front hook which is constructed and arranged to move with trigger rotation, a rear hook which is cooperatively arranged with the front hook and a spring which is positioned between the front hook and the rear hook. The front hook and the trigger are constructed and arranged relative to the safety selector and relative to the hammer in order to allow the hammer to be recocked from an upright position with the safety selector in a “SAFE” position. This particular construction provides a trigger assembly which is constructed and arranged as a two-stage, drop-in trigger assembly which is compliant with the European Standard for an M4/M16 (AR) platform.

Abstract: A trigger assembly for a firearm is disclosed wherein the firearm includes a receiver, a safety selector and a hammer. The trigger assembly includes a trigger having a pivot axis, a front hook which is constructed and arranged to move with trigger rotation, a rear hook which is cooperatively arranged with the front hook and a spring which is positioned between the front hook and the rear hook. The front hook and the trigger are constructed and arranged relative to the safety selector and relative to the hammer in order to allow the hammer to be recocked from an upright position with the safety selector in a “SAFE” position. This particular construction provides a trigger assembly which is constructed and arranged as a two-stage, drop-in trigger assembly which is compliant with the European Standard for an M4/M16 (AR) platform.

Abstract: A trigger assembly for a firearm is disclosed wherein the firearm includes a receiver, a safety selector and a hammer. The trigger assembly includes a trigger having a pivot axis, a front hook which is constructed and arranged to move with trigger rotation, a rear hook which is cooperatively arranged with the front hook and a spring which is positioned between the front hook and the rear hook. The front hook and the trigger are constructed and arranged relative to the safety selector and relative to the hammer in order to allow the hammer to be recocked from an upright position with the safety selector in a “SAFE” position. This particular construction provides a trigger assembly which is constructed and arranged as a two-stage, drop-in trigger assembly which is compliant with the European Standard for an M4/M16 (AR) platform.

Abstract: A trigger assembly for a firearm is disclosed wherein the firearm includes a receiver, a safety selector and a hammer. The trigger assembly includes a trigger having a pivot axis, a front hook which is constructed and arranged to move with trigger rotation, a rear hook which is cooperatively arranged with the front hook and a spring which is positioned between the front hook and the rear hook. The front hook and the trigger are constructed and arranged relative to the safety selector and relative to the hammer in order to allow the hammer to be recocked from an upright position with the safety selector in a “SAFE” position. This particular construction provides a trigger assembly which is constructed and arranged as a two-stage, drop-in trigger assembly which is compliant with the European Standard for an M4/M16 (AR) platform.

Abstract: New and unique improvements of prior known M4/M16 firearms are disclosed that comprise (A) a bolt which, in addition to all of the normal M4/M16 features is configured or reconfigured to accept a bridged extractor spring which straddles the firing pin and presses against the bottom of the extractor with the bridging wire, and (B) a bridged extractor spring which is a single part, wound with dual spaced helical coils connected with a bridge wire that maintains the spacing at the top of the spring. The bridge wire preferably crosses diagonally between and is tangent to both coils.

Abstract: New and unique improvements of prior known M4/M16 firearms are disclosed that comprise (A) a bolt which, in addition to all of the normal M4/M16 features is configured or reconfigured to accept a bridged extractor spring which straddles the firing pin and presses against the bottom of the extractor with the bridging wire, and (B) a bridged extractor spring which is a single part, wound with dual spaced helical coils connected with a bridge wire that maintains the spacing at the top of the spring. The bridge wire preferably crosses diagonally between and is tangent to both coils.