Abstract: A method of removably securing a gas regulating sleeve and a gas line to a rifle by: fluidly coupling a gas block to a bore of a barrel of the rifle; removably locating and securing the gas regulating sleeve in the gas block, the gas line being in fluid communication with the bore via the gas regulating sleeve, and wherein a portion of the gas line is received within an impingement cylinder of a bolt assembly of the rifle when it is in a first position, and wherein the impingement cylinder moves away from the gas line as it moves from the first position to a second position due to gases from the gas block; and wherein the gas regulating sleeve and the gas line are removable from the gas block without disconnecting the barrel from the receiver and without removal of the gas block from the barrel.

Abstract: In accordance with the first exemplary embodiment a semi-automatic M-4 type firearm is provided. The firearm comprises a receiver and a reversible safety selector. The receiver has a right side and a left side. The reversible safety selector is rotatably coupled to the receiver and comprises a shaft with a user selector member at one end. The user selector member is adapted to allow a user to move the reversible safety selector relative to the receiver. The reversible safety selector is adapted to be mounted to the receiver in a first position with the user selector member located on the right side of the receiver. The reversible safety selector may be mounted to the receiver in a second position different from the first position with the user selector member located on the left side of the receiver.

Abstract: A rifle having a receiver with an integral hand guard and a barrel. The barrel is connected to the receiver. The hand guard extends over and surrounds the barrel. A removable hand guard is attached to the receiver by an attachment that stably holds the removable hand guard to the receiver. The attachment is arranged for allowing detachment and removal of the removable hand guard from the receiver without removal of fasteners.

Abstract: An automatic or semiautomatic blackrifle type rifle having a receiver and a bolt carrier movably coupled to the receiver. An action system is connected to the bolt carrier for cycling the bolt carrier in the receiver. A folding butt stock is connected to the receiver, the folding butt stock being both foldable and collapsible.

Abstract: An indirect gas operating system for a semi-automatic or automatic rifle is provided, the indirect gas operating system having: a sleeve removably secured to a forward end of a gas block of the rifle; a piston slidably received within the gas block, wherein the gas block and the sleeve fluidly couple the piston to a bore of a barrel of the rifle; wherein an increase in pressure in the bore of the rifle causes the piston to move away from the sleeve; and wherein the sleeve and the piston are each capable of being removed from the rifle through the forward end of the gas block.

Abstract: A semi-automatic or automatic rifle. The rifle has a receiver having a receiver frame, a barrel removably connected to the receiver frame and a cover coupled to the barrel. A removable hand guard section extends over and generally surrounds the barrel, the removable hand guard section removably connected to the receiver. The removable hand guard section has a locating feature adapted to engage with the cover and locate the hand guard relative to the cover. The barrel has a locking collar adapted to removably position and lock the removable hand guard section relative to the receiver frame and the barrel. The removable hand guard floats in position relative to the barrel.

Abstract: A semi-automatic or automatic rifle is provided. The rifle has a receiver having a receiver frame, a barrel removably connected to the receiver frame, and an end cap coupled to the barrel. A removable hand guard section is provided extending over and generally surrounding the barrel, the removable hand guard section removably connected to the receiver. The removable hand guard section has a locating feature adapted to engage with the end cap and locate the hand guard relative to the end cap. The removable hand guard section has a mounting rail portion and a body portion, the mounting rail portion molded into the body portion. The barrel has a locking collar adapted to removably position and lock the removable hand guard section relative to the receiver frame and the barrel. The removable hand guard floats in position relative to the barrel.

Abstract: A firearm having a lower receiver is provided. The receiver is adapted to couple with a plurality of upper receivers having different calibers. The lower receiver comprises a receiver extension having an opening therein. A spring is disposed within the opening. A buffer member is provided having a first portion having an end. The buffer member is coupled to the spring within the opening, wherein the buffer member is movable between a first position where the end is within the opening and a second position wherein the end external to the opening.

Abstract: A direct gas impingement operating system for an automatic or semi-automatic rifle. The direct gas impingement operating system has a gas block fitted to a barrel having a bore, the gas block in communication with the bore. A gas sleeve is located in the gas block, the gas sleeve in communication with the bore through the gas block. A bolt assembly having an impingement cylinder and a gas line is fitted to the sleeve in communication with the bore through the sleeve and the gas block, the gas line further in fluid communication with the impingement cylinder. Gas discharged from a fired cartridge displaces the impingement cylinder displacing the bolt assembly. The sleeve and the gas line are removable from the gas block without removal of the gas block from the firearm.

Abstract: An automatic or semiautomatic rifle having a receiver and a bolt carrier movably coupled to the receiver. An action system is connected to the bolt carrier for cycling the bolt carrier in the receiver. A receiver extension is connected to the receiver, at least part of the action system extending into the receiver extension. A folding stock is connected to the receiver. The receiver extension is located within the folding stock.

Abstract: A modular automatic or semiautomatic rifle. The rifle has a lower receiver assembly having a fire control assembly for firing the rifle. An upper receiver assembly is provided with a frame and a bolt carrier assembly configured for firing bullets of a predetermined caliber. The lower receiver has a mating interface configured for operably joining the lower receiver assembly to the upper receiver assembly, and for operably joining the lower receiver assembly to another upper receiver assembly different from the upper receiver assembly configured for firing bullets of the predetermined caliber. The other upper receiver assembly has a different frame and different bolt carrier assembly configured for firing bullets of a different predetermined caliber.

Abstract: A direct gas impingement operating system for an automatic or semi-automatic rifle. The direct gas impingement operating system has a gas block fitted to a barrel having a bore, the gas block in communication with the bore. A gas sleeve is located in the gas block, the gas sleeve in communication with the bore through the gas block. A bolt assembly having an impingement cylinder and a gas line is fitted to the sleeve in communication with the bore through the sleeve and the gas block, the gas line further in fluid communication with the impingement cylinder. Gas discharged from a fired cartridge displaces the impingement cylinder displacing the bolt assembly. The sleeve and the gas line are removable from the gas block without removal of the gas block from the firearm.

Abstract: An automatic or semi-automatic rifle. The rifle has a receiver and a bolt having a striking surface, the bolt enclosed within the receiver. A barrel has a bore, the barrel coupled to the receiver. An indirect gas operating system has a cylinder and a piston, the indirect gas operating system mounted with a mounting structure substantially independent of the barrel. The cylinder is in communication with the bore, and the piston is fitted to the cylinder and disposed for striking the striking surface and displacing the bolt assembly.

Abstract: An automatic or semiautomatic blackrifle type rifle having a receiver and a bolt carrier movably coupled to the receiver. An action system is connected to the bolt carrier for cycling the bolt carrier in the receiver. A folding butt stock is connected to the receiver, the folding butt stock being both foldable and collapsible.

Abstract: A semi-automatic or automatic rifle. The rifle has a receiver having a receiver frame, a barrel removably connected to the receiver frame and a cover coupled to the barrel. A removable hand guard section extends over and generally surrounds the barrel, the removable hand guard section removably connected to the receiver. The removable hand guard section has a locating feature adapted to engage with the cover and locate the hand guard relative to the cover. The barrel has a locking collar adapted to removably position and lock the removable hand guard section relative to the receiver frame and the barrel. The removable hand guard floats in position relative to the barrel.

Abstract: A semi-automatic or automatic rifle is provided the rifle having: a receiver having a hand guard portion; a barrel having a bore, the bore removably connected to the receiver, the hand guard portion surrounding at least a portion of the barrel; a gas block having a forward end and a rearward end aligned with the barrel; a sleeve removably secured to the forward end of the gas block; a piston slidably received within the gas block, wherein the gas block and the sleeve fluidly couple the piston to the bore of the barrel; wherein an increase in pressure in the bore of the barrel causes the piston to move away from the sleeve; and wherein the sleeve and the piston are each capable of being removed from the rifle through the forward end of the gas block without removing the gas block from the rifle.

Abstract: A rifle having a receiver with an integral hand guard and a barrel. The barrel is connected to the receiver. The hand guard extends over and surrounds the barrel. A removable hand guard is attached to the receiver by an attachment that stably holds the removable hand guard to the receiver. The attachment is arranged for allowing detachment and removal of the removable hand guard from the receiver without removal of fasteners.

Abstract: An automatic firearm capable of automatic or semiautomatic fire. The firearm has a receiver having a moveable hammer. A selector is rotatably mounted in the receiver. A first sear is rotatably mounted in the receiver to engage the hammer where the first sear contacts a first camming surface of the selector. A second sear is rotatably mounted in the receiver to engage the hammer where the second sear contacts a second camming surface of the selector. A disconnect is rotatably mounted in the receiver where the disconnect contacts a third camming surface of the selector. The selector has a number of selectable positions disposed so that rotation of the selector between a first and last selectable position of the number of selectable positions is less than 180 degrees.

Abstract: An automatic or semiautomatic rifle having a receiver and a bolt carrier movably coupled to the receiver. An action system is connected to the bolt carrier for cycling the bolt carrier in the receiver. A receiver extension is connected to the receiver, at least part of the action system extending into the receiver extension. A folding stock is connected to the receiver. The receiver extension is located within the folding stock.