Limited edition model features a special "Made in the 250th Year of American Liberty" engraving on left side of receiver to commemorate America's 250th Anniversary. Specifications and Features: Limited edition model features a special "Made in the 250th Year of American Liberty" engraving on left side of receiver to commemorate America's 250th Anniversary. Machined from 7075-T6 forged aluminum using mil-spec tolerances. Includes an adjustable tension screw to minimize or eliminate play between the upper and lower receivers.