Automatic rifle gas system
OwnerMichael C. Morrisinventor
Life of this patent
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Abstract
An M16-type automatic rifle is provided with an improved gas operating system. The tube extending forwardly from the bolt carrier key is of such length that it permanently mates with the aftwardly extending gas transfer tube as the bolt carrier key shuttles forward and aftward in operation. This arrangement minimizes fouling by combustion products from the firing of ammunition. Modifications to the gas transfer tube and barrel nut assembly accommodate the extended bolt carrier key tube and facilitate quick change of the barrel in the field with a standard tool.
Claims37
A rifle comprising an upper receiver group, a lower receiver group, and a bolt carrier group,
- said upper receiver group further comprising a barrel, an upper receiver, a cartridge extractor mechanism, and a gas transfer tube communicating with the barrel for the transfer of propellant gas pressure therefrom and extending aftwardly from said point of communication with the barrel towards the upper receiver, said gas transfer tube having an aftmost portion parallel to said barrel;
- said lower receiver group further comprising a trigger mechanism, and a lower receiver adapted to be secured to said upper receiver and together therewith defining a receiver, said lower receiver being adapted to receive an interchangeable magazine adapted to contain a plurality of ammunition cartridges and to feed them individually into said chamber,
- said bolt carrier group comprising a bolt, a firing mechanism associated with and carried by said bolt, an extracting mechanism for extracting spent shells, and a bolt carrier slidably mounted within the receiver for forward and backward reciprocation through a cycle of chambering, firing and extracting a round of ammunition, said bolt carrier having affixed thereto a bolt carrier key, said bolt carrier key having a key tube extending therefrom forwardly along the axis of said aftmost portion of the gas transfer tube, said key tube extending through a port in the upper receiver, said port being of a size to provide sliding clearance for said key tube, said key tube having an internal bore of a diameter sufficient to provide sliding clearance with the external surface of said aftmost portion of the gas transfer tube,
- whereby the key tube slidably engages in mating relationship with the gas transfer tube during the entire firing cycle.
In an M16-type rifle having a bolt carrier key, a gas transfer tube, and an upper receiver, an improved gas system comprising:
- an improved bolt carrier key having a key tube extending therefrom forwardly along the axis of said aftmost portion of the gas transfer tube, said key tube extending through a port in the upper receiver, said port being of a size to provide sliding clearance for said key tube, said key tube having an internal bore of a diameter sufficient to provide sliding clearance with the external surface of said aftmost portion of the gas transfer tube,
- whereby the key tube slidably engages in mating relationship with the gas transfer tube during the entire firing cycle.
A method of modifying an M16-type rifle for improved performance comprising the steps of:
- providing an M16-type rifle having a conventional gas system comprising a bolt carrier key and a gas transfer tube, said gas transfer tube communicating with a barrel through a gas port in said barrel and a front sight assembly contiguous to said barrel, said gas transfer tube extending through a tube port in an upper receiver, said upper receiver being detachably secured to the barrel by a barrel nut assembly comprising a screw-threaded barrel nut;
- providing a bolt carrier key having a key tube extending forwardly therefrom of a length and diameter sufficient to slidably mate with the gas transfer tube throughout an entire firing cycle and substituting it for the original bolt carrier key;
- providing a gas transfer tube which has an aft portion that is coaxial with said key tube along a length sufficient to slidably mate with the key tube throughout an entire firing cycle, said gas transfer tube terminating fore of the upper receiver;
- enlarging the tube port in the upper receiver to a size sufficient to slidably admit the key tube extending forwardly therethrough, and
- providing a barrel nut assembly having each of its elements shaped to slidably admit the key tube extending forwardly therethrough,
- whereby the rifle is thereafter capable of firing an increased number of rounds between necessary cleanings and is capable of having its barrel interchanged in the field by unscrewing the barrel nut with the use of a standard barrel nut wrench.
An improved M16-type rifle comprising an enclosure defining a receiver, a barrel communicating with the receiver, gas-driven reciprocating means for automatically chambering, firing and extracting successive rounds of ammunition fed from magazine means, and means for transferring gas pressure from within the barrel to said reciprocating means;
- wherein said gas-driven reciprocating means comprises a bolt carrier key, said bolt carrier key having a key tube extending therefrom forwardly through a port in the enclosure, said port being of a size to provide sliding clearance for said key tube,
- and wherein said means for transferring gas pressure comprises a gas transfer tube having an aftmost portion coaxial with said key tube,
- said key tube having an internal bore of a diameter sufficient to provide sliding clearance with the external surface of said aftmost portion of the gas transfer tube,
- whereby the key tube slidably engages in mating relationship with the gas transfer tube during the entire firing cycle.
Dependencies are inferred from the claim text.