The 5.7x28mm-chambered CMMG Resolute MK57 is a superb example of a lightweight AR-15. From the butt to the muzzle, this particular model of the Resolute is built with improved characteristics. With a salt-bath nitride finish for long-term durability, the barrel is manufactured of 4140 ChromeMoly steel, which provides outstanding accuracy. The following shots are much simpler thanks to the Zeroed muzzle break that is included with the threaded muzzle. Each rifle comes with an extremely durable Cerakote coating. A full set of CMMG's Zeroed accessories is also included, like an ambidextrous safety selector and an ambidextrous charging handle. The CMMG EML15 handguard has Picatinny rail slots at the front and back of the top of the handguard and M-LOK slots at the 3, 6, and 9 o'clock positions for mounting sights, bipods, lights, lasers, grips, and other accessories. The Mk57 accepts FN Five-seveN style magazines.