Adjustable gas block for an indirect gas operated firearm

Abstract

A firearm including a barrel, receiver, indirect gas system and an adjustable gas block designed to interface with the indirect gas system is provided. Four indexable positions of adjustment are provided for on the adjustable gas block. Positions of adjustment are selected based on the use of a silencer, use of under-powered ammunition, the presence of un-burnt powder and debris in the host firearms operating system, or if the weapon is being fired under “ideal” circumstances. The provided gas block is designed to function with an indirect gas operating system. Excess gas from the operating system is not vented from the gas block thereby generating excess flash and sound. No tool is required to manipulate the adjustment mechanism of the gas.

What is claimed is: 
     
         1 . A firearm utilizing an adjustable gas block comprising:
 a receiver;   a barrel connected to the receiver; a gas operating system;   a piston having a front end, back end, and internal void with means to communicate with the barrel and gas operating system through a plurality of ports which are spaced about the back end;   a gas block housing having a receiving channel with a portion of the barrel contained therein, a cylindrical bore which runs parallel to the axis of the barrel located above the receiving channel with a port in communication with the barrel, the cylindrical bore contains the back end of the piston therein;   a rotatable knob is utilized which both receives and rotates the piston within the cylindrical bore, said knob has a means to retain and rotate the piston within the cylindrical bore.   
     
     
         2 . A firearm utilizing an adjustable gas block in  claim 1  wherein said piston has two ports located about the back end of the piston. 
     
     
         3 . A firearm utilizing an adjustable gas block in  claim 1  wherein said piston has three ports located about the back end of the piston. 
     
     
         4 . A firearm utilizing an adjustable gas block in  claim 1  wherein the rotatable knob provides four positions of adjustment and is removable retrained by a spring loaded detent. 
     
     
         5 . A firearm utilizing an adjustable gas block in  claim 3  wherein at least one of said ports is oversized in proportion to what would be a standard size for the barrel being used with the operating system. 
     
     
         6 . In an indirect gas operated firearm having a receiver, a stock connected to an end of the receiver, a barrel connected to a front of the receiver, a handguard connected to the barrel and a gas operating system, wherein the improvement comprises:
 a gas block with means to secure about the barrel, the gas block housing has a barrel receiving channel with a portion of the barrel therein, the housing also has a piston receiving channel with a portion of the piston contained therein; and   said piston receiving channel has a void which houses an adjustment knob, the adjustment knobs is indexable into four positions; and   a piston is in operational communication with the barrel and the operating system, the piston communicates with the barrel by a series of ports located about its periphery, by rotating the adjustment knob the port of appropriate size is selected and put into communication with the indirect gas operating system and barrel, one port provides a standard flow of gas, one port provides a reduced flow of gas, one port provides a higher than standard flow of gas;   a fourth position of adjustment is provided by the adjustment knob where no port is present on the piston thereby preventing the communication of the barrel with the indirect gas operating system.   
     
     
         7 . In an indirect gas operated firearm having a receiver, a stock connected to an end of the receiver, a barrel connected to a front of the receiver, a hand guard connected to the barrel and a gas operating system as in  claim 6 , wherein the gas block has a porthole communicating with the piston receiving channel, said porthole being located so that the piston is connected to the barrel. 
     
     
         8 . In an indirect gas operated firearm having a receiver, a stock connected to an end of the receiver, a barrel connected to a front of the receiver, a hand guard connected to the barrel and a gas operating system as in  claim 7 , wherein a means is provided to align the gas block with the porthole of the barrel.