Vector Arms V-53 — semi-auto HK33-pattern rifle using roller-delayed blowback in 5.56mm. Built from surplus HK33 parts kits on U.S. receivers. An affordable option for the roller-delayed 5.56 market before PTR entered with the 91 series. Type: Rifle Action: Roller-Delayed Caliber: 5.56x45mm NATO Capacity: 25 Year introduced: 2001, USA Weight: 104 oz Overall length: 43.5" Status: Discontinued Intended use: sport