A selective fire firearm may be provided having a fully automatic open bolt and a semi-automatic closed bolt mode of operation. The firearm may include a trigger group having a trigger prop that ensures that, when the trigger is released in the fully automatic open bolt mode, the bolt carrier stops in an open bolt position held by an open bolt sear. The trigger prop may include a foot that, following a first trigger pull in the fully automatic open bolt mode, slides under and props a rear end of the trigger in a position that allows the open bolt sear to catch the bolt carrier when the trigger is released and propped but prevents the trigger sear from engaging the hammer.
F41A 17/16 - Cook-off prevention, i.e. prevention of spontaneous firing of a cartridge by chamber wall heat
F41A 17/42 - Safeties for locking the breech-block or bolt in a safety position
F41A 17/56 - Sear safeties, i.e. means for rendering ineffective an intermediate lever transmitting trigger movement to firing pin, hammer, bolt or sear
A firearm can have a bolt having a plurality of locking lugs that are configured to have a shear area that is larger than that of a standard M16/M4. A bolt carrier can have a bolt that has a double cut cam having an unlocking cam surface that has sufficient dwell increase to delay a start of unlocking when the bolt carrier is used in an M4 carbine. A stepped extractor pin may be provided that prevents disengagement of the extractor pin. A tube can be configured to provide gas from a barrel of the firearm to the piston via the carrier key. The tube can have a heat radiator formed from triangular shaped threads on at least a portion of the tube. A piston on the bolt and can have a plurality of rings including pairs of mating rings that are formed and maintained as a matched pair.
F41A 15/14 - Cartridge extractors, i.e. devices for pulling cartridges or cartridge cases at least partially out of the cartridge chamber; Cartridge ejectors, i.e. devices for throwing the extracted cartridges or cartridge cases free of the gun for bolt-action guns the ejector being mounted on, or within, the bolt
F41A 3/26 - Rigid bolt locks, i.e. having locking elements rigidly mounted on the bolt or bolt handle and on the barrel or breech-housing respectively the locking elements effecting a rotary movement about the barrel axis, e.g. rotating cylinder bolt locks semi-automatically or automatically operated, e.g. having a slidable bolt-carrier and a rotatable bolt
F41A 3/30 - Interlocking means, e.g. locking lugs, screw threads
F41A 3/62 - Breech mechanism, e.g. locks using combustion gas pressure for adding to the mechanical locking action, or for delaying breech opening movement
F41A 3/70 - Anti-rebound arrangements, i.e. preventing rebound of the bolt out of the firing position
F41A 5/24 - Mechanisms or systems operated by propellant charge energy for automatically opening the lock gas-operated by direct action of gas pressure on bolt or locking elements
A firearm can have a bolt having a plurality of locking lugs that are configured to have a shear area that is at least approximately 1.3 times that of a standard M16/M4. A piston can be formed on the bolt and can have a plurality of rings that are configured to cooperate with the piston to mitigate gas leakage past the piston. Each of the rings can have a key formed thereon and a gap formed therein such that the gap of one ring is configured to receive at least a portion of the key of another ring. The bolt carrier can have a double cut cam.
F41A 3/26 - Rigid bolt locks, i.e. having locking elements rigidly mounted on the bolt or bolt handle and on the barrel or breech-housing respectively the locking elements effecting a rotary movement about the barrel axis, e.g. rotating cylinder bolt locks semi-automatically or automatically operated, e.g. having a slidable bolt-carrier and a rotatable bolt
F41A 3/70 - Anti-rebound arrangements, i.e. preventing rebound of the bolt out of the firing position
F41A 5/24 - Mechanisms or systems operated by propellant charge energy for automatically opening the lock gas-operated by direct action of gas pressure on bolt or locking elements
F16J 9/16 - Joint-closures obtained by stacking of rings
F41A 13/12 - Systems for cooling the outer surface of the barrel
F41A 3/14 - Rigid bolt locks, i.e. having locking elements rigidly mounted on the bolt or bolt handle and on the barrel or breech-housing respectively
F41A 21/24 - Barrels or gun tubes with fins or ribs, e.g. for cooling
F41A 3/26 - Rigid bolt locks, i.e. having locking elements rigidly mounted on the bolt or bolt handle and on the barrel or breech-housing respectively the locking elements effecting a rotary movement about the barrel axis, e.g. rotating cylinder bolt locks semi-automatically or automatically operated, e.g. having a slidable bolt-carrier and a rotatable bolt
F41A 3/64 - Mounting of breech-blocks; Accessories for breech-blocks or breech-block mountings
F41A 3/70 - Anti-rebound arrangements, i.e. preventing rebound of the bolt out of the firing position
F41A 3/84 - Coil spring buffers mounted within the gun stock
F41A 3/72 - Operating handles or levers; Mounting thereof in breech-blocks or bolts
F41A 5/18 - Mechanisms or systems operated by propellant charge energy for automatically opening the lock gas-operated
F41A 5/26 - Arrangements or systems for bleeding the gas from the barrel
F41A 11/00 - Assembly or disassembly features; Modular concepts; Articulated or collapsible guns
F41A 5/24 - Mechanisms or systems operated by propellant charge energy for automatically opening the lock gas-operated by direct action of gas pressure on bolt or locking elements
F41A 17/64 - Firing-pin safeties, i.e. means for preventing movement of slidably-mounted strikers
F41A 19/42 - Mechanical firing mechanisms having at least one hammer
F41A 15/14 - Cartridge extractors, i.e. devices for pulling cartridges or cartridge cases at least partially out of the cartridge chamber; Cartridge ejectors, i.e. devices for throwing the extracted cartridges or cartridge cases free of the gun for bolt-action guns the ejector being mounted on, or within, the bolt
F41A 19/13 - Percussion or firing pins, i.e. fixed or slidably- mounted striker elements; Mountings therefor
A box magazine for a firearm may have a housing with two substantially different widths. A wider region may accommodate four columns of cartridges and may have tapered surfaces at one end that lead into a narrower region which may accommodate an interlocked and staggered double column of cartridges. Cartridges in the wider region may be separated into two staggered double columns by a free standing dividing wall and may be advanced by inner and outer contoured followers that may be nested together to form a single follower assembly surrounding the freestanding wall and that may be driven by the outer follower's spring. An inner follower spring may remain nested within the outer follower such that the two followers coordinate the advance of the two separated double columns of cartridges toward tapered surfaces that merge the two double columns into two single columns proximate the top of the dividing wall.
A high capacity box magazine (100) is provided. A plurality of nested followers (161,162) may be adapted to nest one within another and a plurality of springs (150-152) may be configured to nest one within another to facilitate the advancement of cartridges within the box magazine to a firearm. A spring cup (160) or cups may be used to nest additional springs that work in series and are nested within each other to further reduce the required height of the springs. The reliability of a conventional lower capacity box magazine may be maintained or exceeded without requiring significantly greater length in order to accommodate the increased capacity. The high capacity box magazine typically requires less frequent magazine changes than conventional lower capacity box magazines.
patents
