5.7x28mm has quickly become the personal defense weapon caliber of choice for many. Offering near .22 LR levels of recoil and performance that rivals 5.56mm at close range it’s no surprise why. Even with a 5 barrel this BANSHEE sacrifices nothing when it comes to features. The Mk57 platform is designed to use FN®* Five-seveN®* pattern magazines and still offers the full range of AR15 operational features like last round bolt hold open and can utilize standard AR15 triggers. - Platform Mk57 - Caliber 5.7x28mm - Operating System Radial Delayed Blowback - Barrel Length 5 - Barrel Twist 1:9 - Barrel Contour MT - Barrel Material 4140CM SBN - Barrel Twist 1:9 - Muzzle Device CMMG ZEROED Linear Compensator - Muzzle Thread 1/2 x 28 - Upper Receiver Billet 6061 T6 Aluminum - Lower Receiver Mk57 Forged 7075 T6 Aluminum - Hand Guard CMMG EML4 M-LOK - Finish Cerakote Standard - Charging Handle CMMG ZEROED Ambi - Pistol Grip CMMG ZEROED Pistol Grip - Buffer Type Carbine - Receiver Extension CMMG 6 Position Fastback Extension - Stock / Brace CMMG RipBrace - Trigger Type ZEROED Drop-In Single Stage - Trigger Guard Integrated - Safety Selector CMMG ZEROED 60/90 Degree - Magazine 20rd Promag - Weight 4.8 lbs - Length 20.9