The POF-USA gas piston operating system has an adjustable gas block that controls the amount of gas that is used to cycle the bolt carrier.

The notched side of the gas plug denotes that it is in “NORMAL” mode when it is facing up. The rifle should cycle normally with most commercial ammunition.

Depress the gas plug detent; rotate the gas plug 45° so the gas plug detent is facing at a 45° angle, this denotes that the gas plug is in ADVERSE mode using less gas to compensate for some ammunition.

Depressing the detent and rotating to the 90° position denotes that the gas plug is in “OFF” mode. This shuts off the gas from the gas block completely and causes the rifle to function as a single-shot rifle.

By depressing the gas plug detent and rotating the gas plug 180° from “NORMAL” mode, the smooth side of the gas plug is now facing up. The firearm is now in “SUPPRESSED” mode. Gas in this mode is restricted to compensate for the added backpressure from a suppressor. A second suppressed mode setting is available with an increased gas flow which may be required with some suppressors. Depress the gas plug detent and rotate the smooth face to a 45° angle, this denotes that the gas plug is in the “SUPPRESSED2” mode.


Putting a suppressor on your firearm changes the cycling characteristics of the host. In doing so causes unwanted malfunctions and increased wear on the system. Please be aware of all risk by attaching a suppressor.

5 position piston firearm Gas Plug orientation guide
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