--- title: "Sig Sauer MCX Rattler .300 BLK Firearm" description: "Compact Sig Sauer MCX Rattler chambered in .300 BLK with a 5.5-inch barrel, gas-piston system, M-LOK handguard, and 30+1 capacity." canonical_url: "https://www.kygunco.com/product/sig-sauer-qp-only-mcx-300-blk-pistol-5.5-blk-no-stock-30rd" meta: author: KYGUNCO "og:description": "Compact Sig Sauer MCX Rattler chambered in .300 BLK with a 5.5-inch barrel, gas-piston system, M-LOK handguard, and 30+1 capacity." "og:image": "https://cdn.kygunco.com/assets/products/262935/thumbnail.jpg?v=1729537424" "og:image:height": "500" "og:image:width": "500" "og:title": "Sig Sauer MCX Rattler .300 BLK Firearm" --- > Index of every page on this site: [llms.txt](https://www.kygunco.com/llms.txt) [Home](https://www.kygunco.com/) / [Shooting](https://www.kygunco.com/category/shooting) / [Guns](https://www.kygunco.com/category/shooting/guns) / [Handguns](https://www.kygunco.com/category/shooting/guns/handguns) / [Semi-Auto](https://www.kygunco.com/category/shooting/guns/handguns/semi-auto) / SGS-WPMCX-300B-5B-TAP ![Main product image](https://static.kygunco.com/cdn-cgi/image/f=auto,w=600/assets/products/262935/main.jpg?v=1729537424) For illustration purposes only, this image may not be an exact representation of the product. # SIG SAUER MCX 300 AAC Blackout 5.5" 30rd - QP ONLY The SIG Sauer MCX Rattler is a compact semi-automatic firearm chambered in .300 BLK. It features a 5.5-inch barrel, gas-piston operation, free-floating M-LOK handguard, folding pivoting contour, black finish, and a 30+1 capacity with one magazine included. $2,270.99 ** 5 interest-free payments of **$454.20** with ![Sezzle logo](https://www.kygunco.com/brands/sezzle.svg) ** ![Credova logo](https://www.kygunco.com/brands/credova.svg) As low as **$214.74**/month with ![Credova text logo](https://www.kygunco.com/brands/credova-text.svg) ** Online In Store ** Free Shipping Enjoy delivery to the Lower 48 States at no cost. [** Qualified Professionals Only Learn more about KYGUNCO's Qualified Professional program.**](https://www.kygunco.com/page/qualified-professionals) ** Ships To FFL Dealer Handled by our expert shippers in Bardstown, KY. ** Check Local Restrictions Not sure whether this item can be shipped to your area? Enter your ZIP code for a quick check. Almost gone. Order now before it sells out. Item # 262935 Style WPMCX-300B-5B-TAP UPC 798681608935 Condition New Manufacturer [Sig Sauer](https://www.kygunco.com/brand/sig-sauer) Model MCX Round Capacity 30 Caliber 300 AAC Blackout Action Semi-Auto Barrel Length 5.5 in Rapid deployment, thin, agile and precise. This is the SIG MCX® Rattler. Featuring a 5.5" PDW barrel, the MCX platform has never been more compact or accessible. Ready to go wherever it's needed, the MCX Rattler PCB features a folding pivoting contour for stability and easy concealment. This gun was designed from the ground up to be as discrete as possible while retaining all the robust capabilities of the MCX. Free-floating M-LOK® handguards matched with a PDW upper and 5.5" barrel, the MCX Rattler PCB is the ideal choice for fast-moving operators. ### Details and Features: - Action: Semi-Auto - Caliber: .300 BLK - Capacity: 30 + 1 - Magazines: One - Barrel Length: 5.5 Inches - Twist Rate: 1.5" - Thread Pattern: 5/8x24 tpi - Weight: 5.1 lbs - Operating System: Gas Piston - Pistol Brace: None - Color: Black Shop with KYGUNCO for the best selection, competitive pricing, and exceptional customer service. Experience the difference that comes with buying from a trusted outdoor retailer with over 20 years of experience in the industry. ** WARNING: This product contains chemicals known to the State of California to cause cancer, birth defects, or other reproductive harm. For more information, go to [www.p65warnings.ca.gov](https://www.p65warnings.ca.gov). 0.0 ** ** ** ** ** 0 reviews ** ** ** ** ** 0 ** ** ** ** ** 0 ** ** ** ** ** 0 ** ** ** ** ** 0 ** ** ** ** ** 0 ## Don't Forget Your Ammo ```json {"@context":"https://schema.org","@graph":[{"@id":"https://www.kygunco.com/#website","@type":"WebSite","description":"Shop KYGUNCO for firearms, ammo, accessories, parts, and outdoor gear at low prices with fast, easy nationwide shipping.","name":"KYGUNCO","url":"https://www.kygunco.com/","publisher":{"@id":"https://www.kygunco.com/#/schema/organization/kygunco"}},{"@id":"https://www.kygunco.com/product/sig-sauer-qp-only-mcx-300-blk-pistol-5.5-blk-no-stock-30rd#webpage","@type":"WebPage","description":"Compact Sig Sauer MCX Rattler chambered in .300 BLK with a 5.5-inch barrel, gas-piston system, M-LOK handguard, and 30+1 capacity.","name":"Sig Sauer MCX Rattler .300 BLK 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