Spindle valve for the M14, with replaceable gas jets. These valves come with jets in 0.052″, 0.055″, 0.059″, and 0.062″ (custom sizes can be made upon request). There is a benefit to limiting gas flow with heavier loads, or when firing suppressed, as these conditions cause greater back-pressure, and put more gas into the cylinder, possibly damaging the op-rod, or the brass. The stock barrel has a 0.076″ diameter gas port, and all downstream holes are larger, so it is the gas port that determines how much gas flows into the cylinder. For high pressure, solutions do exist to add a vent to the gas plug, but it makes more sense to limit the gas flowing into the cylinder in the first place, rather than trying to vent it after it gets there.
These are new production valves that have a tapped hole in them, so the included stainless gas jets can be screwed in to regulate gas flow. Sizes included are 0.052”, 0.055″, 0.059″, 0.062″. With these, the two valve positions will be Off/Reduced.