A regulated gas block assembly may include a gas block including a barrel receiving bore, a gas tube receiving bore, and an intermediate passage extending from the barrel receiving bore to the gas tube receiving bore. The intermediate passage may be oriented at an oblique angle with respect to the barrel receiving bore. The intermediate passage may include a gas regulator seat, and a gas regulator may be positioned and removably secured in the gas regulator seat. A barrel including a gas ring recess may be fit to the regulated gas block assembly.

A regulated gas block assembly may include a gas block including a barrel receiving bore, a gas tube receiving bore, and an intermediate passage extending from the barrel receiving bore to the gas tube receiving bore. The intermediate passage may be oriented at an oblique angle with respect to the barrel receiving bore. The intermediate passage may include a gas regulator seat, and a gas regulator may be positioned and removably secured in the gas regulator seat. A barrel including a gas ring recess may be fit to the regulated gas block assembly.

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.

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.

Gas-operated firearms, in which the gas system guides gas selectively from the gas removal bore to a gas pipe, with a platelet, movable between at least two positions in the gas system. The platelet may be pivotable about a pivot axis pin. A stop pin, parallel to the pivot axis pin, may protrude into a stop bore of the platelet, thus delimiting the pivoting. The platelet may have at least two recessed catch positions, into which a catch, under the effect of a catch spring, optionally engages, provided that the gas through-bore associated with the catch comes to rest in alignment between the gas bores when the catch engages in one of the recesses.

Gas-operated firearms, in which the gas system guides gas selectively from the gas removal bore to a gas pipe, with a platelet, movable between at least two positions in the gas system. The platelet may be pivotable about a pivot axis pin. A stop pin, parallel to the pivot axis pin, may protrude into a stop bore of the platelet, thus delimiting the pivoting. The platelet may have at least two recessed catch positions, into which a catch, under the effect of a catch spring, optionally engages, provided that the gas through-bore associated with the catch comes to rest in alignment between the gas bores when the catch engages in one of the recesses.

Firearms, with gas-operated reloading, having a gas block that includes a gas pressure selector movable between at least two positions. For smooth operation, the gas pressure selector in the gas block is rotatable into at least two positions about its primary axis and is also designed to be axially displaceable along the same primary axis between at least two positions. The gas block includes a stop pin that is arranged to cooperate with a control surface of the gas pressure selector with complementary form and function, and further includes a locking device having a spring-loaded locking pin that can yield normally to the primary axis to temporarily lock the gas pressure selector in a predetermined position.

Firearms, with gas-operated reloading, having a gas block that includes a gas pressure selector movable between at least two positions. For smooth operation, the gas pressure selector in the gas block is rotatable into at least two positions about its primary axis and is also designed to be axially displaceable along the same primary axis between at least two positions. The gas block includes a stop pin that is arranged to cooperate with a control surface of the gas pressure selector with complementary form and function, and further includes a locking device having a spring-loaded locking pin that can yield normally to the primary axis to temporarily lock the gas pressure selector in a predetermined position.

A semiautomatic shotgun comprising a receiver, a barrel, a forward gas block assembly attached to the barrel, a slider assembly rearward of the gas block assembly extending into the receiver. Upon firing a shotshell the explosive gases in the barrel are diverted through two ports into the gas block assembly, specifically into a pair of lateral pressure relief valves positioned on both sides of the barrel. The pressure relief valves further having a gas pathway to a piston chamber. A piston is forced rearwardly and engages a slider of the slider assembly that is linked to a breech block in the receiver. The breech block loads unfired shells and ejects the fired shells accomplishing the semiautomatic recycling. The dual pressure relief valves actuate to moderate and limit the gas pressure that enters the piston chamber when using shotshells of different power levels thereby providing consistency in the recycling operation.

A semiautomatic shotgun comprising a receiver, a barrel, a forward gas block assembly attached to the barrel, a slider assembly rearward of the gas block assembly extending into the receiver. Upon firing a shotshell the explosive gases in the barrel are diverted through two ports into the gas block assembly, specifically into a pair of lateral pressure relief valves positioned on both sides of the barrel. The pressure relief valves further having a gas pathway to a piston chamber. A piston is forced rearwardly and engages a slider of the slider assembly that is linked to a breech block in the receiver. The breech block loads unfired shells and ejects the fired shells accomplishing the semiautomatic recycling. The dual pressure relief valves actuate to moderate and limit the gas pressure that enters the piston chamber when using shotshells of different power levels thereby providing consistency in the recycling operation.