Sig MCX OMEGA Valve Mod. 2-S (300BLK, Shorter)

Patent Pending

BACKORDER RESERVES ARE OUT OF STOCK. My manufacturing partners and I are working as fast as we can to get current orders awaiting fulfillment out the door. There will be a restock (with valves on hand, NOT backordered) in approximately two weeks (as of 8/19/25). Sign up for the newsletter on the homepage if you would like to be notified!

View data here. This table can serve simply to give you an idea of some potential starting points.

USPS Disclaimer: I am hereby advising you to choose UPS. Do not harass me if USPS is slow!

The OMEGA Valve is the first tunable gas valve for the Sig Sauer MCX. It is made from 17-4 stainless steel via additive DMLS manufacturing, and is coated in an advanced hexagonal boron nitride coating.

It does three things:

1. Instead of indexing on a ball detent within the gas block, it indexes on the gas valve retaining pin, allowing for four gas positions as opposed to the original two.
2. The Mod.2-S is unique in that it utilizes recessed, tapered ports to accelerate the velocity of the gas as it enters the expansion chamber of the Valve, improving reliability with a wider array of ammunition.
3. It utilizes Parker Mountain Machine SCAR gas jet screws, allowing the user to vent excess gas out of the front of the OMEGA Valve. Also available are my own Micro Jet Screws to allow even finer tuning of your system!

I highly recommend consulting the data table and considering Micro Jets if you are using silencers that utilize modern hybrid technologies.

When dialed in correctly, the OMEGA Valve will transform your experience with the Sig MCX. You will experience a softer recoil impulse, a less severe at-ear sound signature (when shooting with a silencer), and marginally reduced exposure to toxic gas, regardless of what ammunition and silencer you choose to use. Please note that the OMEGA Valve was designed to tune suppressed performance. Satisfactory results may be possible to achieve in the unsuppressed state with subsonic ammunition, but this is either unpublished or untested as of 06/07/25. The weapon should cycle some unsuppressed subsonic ammo, but lock-back is not guaranteed. The Mod. 2-S was specifically designed to enhance reliability across different ammunition loads and silencers when used with the shorter MCX barrels, and venting will almost certainly be recommended for supersonic ammunition.

A special note about the short barrels: IF you are using a silencer with excessively high back pressure, you may be able to use the Mod. 2-L in barrels shorter than 9 inches.

With your order, you will receive:

• (1) OMEGA Valve Mod. 2-S
• (1) Solid Set Screw (already installed)
• (1) 2.5mm wrench

Want supreme reliability and more room to tune? Consider adding a JP Enterprises Enhanced Gas Ring to your order!

This model has been tested to work with the Sig Sauer MCX Rattler, TACOPS, and Spear  LT line of 300BLK rifles, specifically, the shorter 5.5" and 6.75" variants.  I do not recommend using the Mod. 2-S in barrels longer than 6.75 inches. It won't necessarily hurt anything, but the weapon will over-function. At this time, I am inclined to believe that it is unlikely that they will fit in Legacy (Gen 1) barrels. See the FAQ for additional information regarding compatibility and adjustment.

Be advised: not all valves print equally, and some must be sanded and/or turned down to fit into spec and may have a more "polished" finish than others. 

We have data available to be viewed here.