Firearm with rear regulator

Abstract

An M-4 type firearm is provided. The M-4 type firearm having a receiver with a bolt carrier movably located therein. A receiver extension is connected to the receiver with the receiver extension including a spring loaded bolt carrier buffer movable relative to the receiver for effecting return of the bolt carrier to a firing position of the bolt carrier. A regulator is provided on the receiver extension, for enabling movement of the bolt carrier buffer relative to the receiver and effecting automatic or semi-automatic fire when the receiver extension is at least partially filled with water.

1 . An M-4 type firearm comprising: 
 a receiver with a bolt carrier movably located therein;    a receiver extension connected to the receiver, the receiver extension including a spring loaded bolt carrier buffer movable relative to the receiver for effecting return of the bolt carrier to a firing position of the bolt carrier; and    a regulator, on the receiver extension, for enabling movement of the bolt carrier buffer relative to the receiver and effecting automatic or semi-automatic fire when the receiver extension is at least partially filled with water.    
     
     
         2 . The M-4 type firearm of  claim 1 , wherein, the regulator effects selection of a cycle rate of the bolt carrier between a first cycle rate and a different second cycle rate.  
     
     
         3 . The M-4 type firearm of  claim 1 , wherein, the regulator is selectably positionable in different selectable positions each of which effects a different firing rate of the firearm so that the firearm has a range of different firing rates, and wherein changing regulator position between different selectable positions changes the firing rate.  
     
     
         4 . The M-4 type firearm of  claim 1 , wherein, the regulator is selectably positionable to a sealed position, and wherein, the regulator in the sealed position seals an interior of the receiver extension to an exterior of the receiver extension.  
     
     
         5 . The M-4 type firearm of  claim 1  further comprising a barrel coupled to the receiver and an indirect gas operating system coupled to the barrel, wherein, the indirect gas operating system cycles the bolt carrier from the firing position into the receiver extension.  
     
     
         6 . The M-4 type firearm of  claim 1 , wherein, the receiver extension further comprises an integral stock support.  
     
     
         7 . The M-4 type firearm of  claim 1 , wherein, the regulator comprises a rotatable selector coupled to the receiver extension, and wherein, the receiver extension further comprises a passage in fluid communication with the regulator, and wherein, the regulator is selectably positionable to effect selection of a firing rate from a range of different firing rates.  
     
     
         8 . An M-4 type firearm comprising: 
 a receiver with a bolt carrier movably located therein;    a receiver extension connected to the receiver, the receiver extension enclosing a bolt carrier return spring; and    a regulator valve coupled to the receiver extension;    wherein, the bolt carrier return spring effects return of the bolt carrier to a firing position, and wherein, the regulator valve regulates a firing rate of the firearm.    
     
     
         9 . The M-4 type firearm of  claim 8 , wherein, the regulator valve has different selectable settings corresponding to different selectable automatic firing cycle rates.  
     
     
         10 . The M-4 type firearm of  claim 8 , wherein, the receiver extension has at least one port interfacing with the regulator valve, and wherein the regulator valve regulates a fluid flow rate through the port.  
     
     
         11 . The M-4 type firearm of  claim 8 , further comprising a barrel coupled to the receiver and an indirect gas operating system coupled to the barrel, wherein, the indirect gas operating system cycles the bolt carrier from the firing position into the receiver extension.  
     
     
         12 . The M-4 type firearm of  claim 8 , wherein, the receiver extension has a port interfacing with the regulator valve, and wherein, the regulator valve is selectably positionable from a first position closing the port to a second position opening the port.  
     
     
         13 . The M-4 type firearm of  claim 8 , wherein, the regulator valve is capable of adjustment by an operator to enable the M-4 type firearm to be fired substantially immediately upon removal from water.  
     
     
         14 . The M-4 type firearm of  claim 8 , wherein, the regulator valve has a spring loaded engagement adapted to positively engage hold the regulator valve in a selectable position relative to the receiver extension.  
     
     
         15 . An M-4 type firearm comprising: 
 a receiver having a bolt carrier movably located therein;    a barrel coupled to the receiver;    a receiver extension connected to the receiver, the receiver extension having a bolt carrier return spring;    an indirect gas operating system coupled to the barrel; and    a cycle rate selector mounted on the receiver extension;    wherein, the indirect gas operating system and the bolt carrier return spring cooperate to cycle the bolt carrier in the receiver, and wherein, the cycle rate selector regulates automatic firing cycle rate of the firearm.    
     
     
         16 . The M-4 type firearm of  claim 15 , wherein, the cycle rate selector regulates gas flow within the receiver extension, and wherein, the gas flow results from the cycling bolt carrier.  
     
     
         17 . The M-4 type firearm of  claim 15 , wherein, the receiver extension has a plurality of ports interfacing with the cycle rate selector, wherein, the cycle rate selector is selectably positionable from a first position closing at least on port of the plurality of ports to a second position opening the at least one port, and wherein, the cycle rate selector further comprises a seal, the seal adapted to seal the at least one port when the cycle rate selector is in the first position.  
     
     
         18 . The M-4 type firearm of  claim 17 , wherein, when in the second position, the cycle rate selector enables movement of the bolt carrier effecting automatic or semi-automatic fire when the receiver extension is at least partially filled with water.  
     
     
         19 . The M-4 type firearm of  claim 15 , wherein, the receiver extension is of one piece unitary construction, and wherein the receiver extension further comprises an integral stock support.  
     
     
         20 . The M-4 type firearm of  claim 15 , wherein, the cycle rate selector comprises a valve having a gasket, the valve being rotatably coupled to the receiver.  
     
     
         21 . The M-4 type firearm of  claim 15 , wherein, the cycle rate selector comprises a valve having a port and a gasket, and wherein, the valve is rotatably coupled to the receiver, and wherein rotation of the valve variably regulates automatic firing cycle rate over a range of automatic firing cycle rates.  
     
     
         22 . An automatic firearm comprising: 
 a receiver having a bolt carrier movably located in an interior of the receiver;    a receiver extension connected to the receiver, the receiver extension having an interior passage through which the interior of the receiver communicates with an exterior of the firearm;    a closure coupled to the receiver extension, the closure being selectably movable between opened and closed positions;    wherein, the closure in the closed position is more restrictive on fluid flow through the interior passage than when the closure is in the opened position.