The Geissele Super Duty in Super Black Nitride finish is a variant of the standard Super Duty featuring Geissele's Super Black Nitride coating on the barrel and major components. The 16-inch barrel, MK16 rail, and SSAE trigger remain identical to the standard Super Duty with the finish change providing improved corrosion resistance. Type: Semi-Auto Rifle Action: Direct Impingement Caliber: 5.56x45mm Capacity: 30 Year introduced: 2020, USA Weight: 7 oz Overall length: 32.5" Status: Active Military use: Yes Intended use: Duty, Military, Range