Guns CMMG now offering 5.56mm caliber option for AR15 pistols Recoil Staff July 11, 2014 Join the Conversation At RECOIL, we review every product fairly and without bias. Making a purchase through one of our links may earn us a small commission, and helps support independent gun reviews. Learn More Find out more about how we test products. CMMG is adding a 5.56mm option to its line of AR pistols. In addition to the new caliber, the Mk4 K AR Pistol features a 12.5 in. barrel (vs. the 8.2 in. versions in .300 AAC Blackout and 9mm). The new Mk4 K comes with a Magpul MOE grip and stock, an A2 muzzle comp and an ambi rear sling mount. The Mk4's rails are RKM11 free-floating KeyMod (slots at 3, 6 and 9:00 positions) with a Pic rail across the top. As with other CMMG firearms, the Mk4 K AR Pistol comes with a lifetime guarantee against defect in material or workmanship. Learn more on their website, Facebook page, YouTube channel or via Twitter. Why you can trust RECOIL Since our founding in 2012, RECOIL remains the premier firearms lifestyle publication for the modern shooting enthusiast. We deliver cutting-edge coverage of guns, gear, accessories and technology. We go beyond basic reviews, providing no B.S. buyer’s guides, hands-on testing and expert analysis on everything from firearms and survival equipment to watches and vehicles. Our reviewers are the backbone of our operation and come from diverse shooting backgrounds: Former law enforcement, military veterans, competitive shooters, seasoned hunters and plain old firearms enthusiasts. Furthermore, we’re not just gun experts, but dedicated journalists who adhere to the strictest standards of our profession. At RECOIL, editorial independence is the foundation of everything we publish and the cornerstone of reader trust. Our editors, writers and content creators make all editorial decisions independently, free from outside influence. That boils down to: advertisers don’t dictate our coverage, the outcomes of our reviews or what we recommend in our buyer’s guides. First and always, our commitment is to our audience—ensuring every review and article is accurate, unbiased, and driven by real-world experience. Whether you’re selecting your next firearm, upgrading your gear, or exploring the latest innovations in the shooting world, RECOIL provides the trusted insights you need to make informed decisions. Learn more about our Editorial Standards and how we review products. NEXT STEP: Download Your Free Target Pack from RECOILFor years, RECOIL magazine has treated its readers to a full-size (sometimes full color!) shooting target tucked into each big issue. Now we've compiled over 50 of our most popular targets into this one digital PDF download. From handgun drills to AR-15 practice, these 50+ targets have you covered. Print off as many as you like (ammo not included). Get your pack of 50 Print-at-Home targets when you subscribe to the RECOIL email newsletter. We'll send you weekly updates on guns, gear, industry news, and special offers from leading manufacturers - your guide to the firearms lifestyle.You want this. Trust Us.
