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.