The MPA Defence Industries Viper is based on the Specna Arms C12. The rifle is completely stripped and rebuilt using custom parts to guarantee performance. The gearbox is cleaned, re-shimmed and greased using high-performance grease. A basic Titan trigger is fitted this can be upgraded if required. A CNC hop unit is fitted with a matched high-performance rubber and nub. The rifle is then fully tested to ensure it meets quality control specifications.