I had been looking for a way to keep a MK31, MK79 and MK 80 Flare Projector (flare pen launcher used by pilots and ground troops) handy w/o using a string around my neck or a mini flash light holder on the belt. Finally a company has made something. 
The current troops use these pen lauchers as a second last line of notice / defense (escalation-of-force) to an oncoming vehicle. They had the same issue, could not get to it fast enough. Now with this clamp for the M4 rail system, it is right at the end of the barrel of the M4 / M16 / AR-15 rail system.
The LT-663 mounts the Mk31 launcher to any mil-spec picatinny rail using a standard LT-171 mount When mounted on the left rail, the flare can be launched with a flick of the thumb, with the weapon trained on target. Machined from solid billet aluminum, it is built for abuse, and takes only seconds to install. The LT-663 comes complete with LT-171 mount, QD adjustment wrench, vial of blue Locktite and Instructions.
Link for this LaRue product
http://stores.homestead.com/Laruetactical/Detail.bok?no=186
This is the MK31 Launcher and together with the MK80 Flares makes the MK79 Projector Kit.
The LaRue LT-663 Rail Clamp for the MK31, MK79 and MK80
The current troops use these pen lauchers as a second last line of notice / defense (escalation-of-force) to an oncoming vehicle. They had the same issue, could not get to it fast enough. Now with this clamp for the M4 rail system, it is right at the end of the barrel of the M4 / M16 / AR-15 rail system.
The LT-663 mounts the Mk31 launcher to any mil-spec picatinny rail using a standard LT-171 mount When mounted on the left rail, the flare can be launched with a flick of the thumb, with the weapon trained on target. Machined from solid billet aluminum, it is built for abuse, and takes only seconds to install. The LT-663 comes complete with LT-171 mount, QD adjustment wrench, vial of blue Locktite and Instructions.
Link for this LaRue product
http://stores.homestead.com/Laruetactical/Detail.bok?no=186
This is the MK31 Launcher and together with the MK80 Flares makes the MK79 Projector Kit.
The LaRue LT-663 Rail Clamp for the MK31, MK79 and MK80