Gas Operated Semi Automatic Firearm Exclusion Act
Fortunately, this thing has no chance of becoming law – see the full story at The Reload:
https://thereload.com/senate-democrats-introduce-broad-new-gun-ammo-magazine-ban-bill/
There’s so much more weird stuff in the bill, but I will leave all those bits to the more politically oriented folks.
Text of the bill here:
https://www.heinrich.senate.gov/imo/media/doc/gosafe_bill_text.pdf
Relevant definitions:
(40) The term ‘gas-operated’, with respect to a semi-automatic firearm, means any firearm that harnesses or traps a portion of the high-pressure gas from a fired cartridge to cycle the action using —
(A) a long stroke piston, where gas is vented from the barrel to a piston that is mechanically fixed to the bolt group and moves to cycle the action;
(B) a short stroke piston, where gas is vented from the barrel to a piston that moves separately from the bolt group so that the energy is imparted through a gas piston to cycle the action;
(C) a system that traps and vents gas from either the barrel or the chamber to directly strike or impinge the bolt, bolt carrier, or slide assembly, to unlock and cycle the action;
(D) a hybrid system that combines elements of a system described in subparagraph (C) with a system described in subparagraph (A) or (B) to capture gas vented from the barrel to cycle the action;
(E) a blowback-operated system that directly utilizes the expanding gases of the ignited propellant powder acting on the cartridge case to drive the breechblock or breech bolt rearward; or
(F) a recoil-operated system that utilizes the recoil force to unlock the breech bolt and then to complete the cycle of extracting, ejecting, and reloading.