The Sig Sauer MCX (brand part no. RMCX-300B-9B-IR-SBR) is a .300 AAC Blackout short-barreled rifle, pairing a 9-inch barrel and a 1-in-5 twist rate for a compact, maneuverable platform. Sig Sauer builds the MCX with a 30-round capacity. The MCX favors shooters who want a compact, NFA-registered SBR platform.

Key Specifications

• Chambered in .300 AAC Blackout for compact SBR performance.
• Wears a 9-inch barrel for a compact SBR profile.
• Cut with a 1-in-5 twist rate.
• Feeds from a 30-round capacity configuration.
• Operates as a Semi-Auto action.
• Finished in FDE.
• Includes 1 x 30-Round magazine.

Frequently Asked Questions

Is this an NFA item? Yes. As a short-barreled rifle (SBR), it's a Title II firearm requiring an approved ATF Form 4 and transfer through an NFA-licensed dealer.

What caliber does it fire? .300 AAC Blackout.

How long is the barrel? 9 inches.

Buy the Sig Sauer MCX SBR

This is a Title II item regulated under the National Firearms Act. Purchase requires an approved ATF Form 4, no federal transfer tax and transfer through a licensed NFA (SOT/Class 3) dealer, with an extended federal approval wait before delivery. Order through Sig Sauer‘s short barrel rifles lineup and our Lubbock, Texas team will walk you through the transfer process.