Maxim Defense Industries MDX 510C, Semi-automatic Rifle, SBR, 300 Blackout, 10.3 Barrel, Adjustable Gas Block, MLOK Handguard, HATEBRAKE Muzzle Booster, Anodized Finish, Black, BCM Gunfighter Grip, Maxim SCW Stock, ALG Defense Combat Trigger, Radian Raptor Charging Handle, Radian Talon Ambidextrous Safety, 1 Magazine, 30 Rounds MXM-47985 Comfort and compactness, the 10.3" barrel length of the MDX-510 has always been a staple for CQB firearms. The MDX series was designed and tested to handle the fierce demands of the Tier 1 community. The right upgrades, features, and technology make sure the MDX-510 will stand up to whatever you put it through. Each MDX-510 is supplied with a Gen 7 CQB stock. The CQB system combines form and function flawlessly. Adding just 5.3" to the receiver when fully compact, yet extending fully to 10", you get a compact package with the full length-of-pull of standard carbine stocks. The MDX series firearms are also equipped with Maxim's HATEBRAKE muzzle booster. This patent-pending device significantly reduces recoil, decreases the flash signature, pushes gasses and concussion waves downrange away from the operator and improves overall performance in short barrel pistols and rifles.