AAC Ranger Front End Cap, 30 cal. The AAC Ranger front end cap does eliminate a lot of the flash that would come with standard .30 Cal ammo on an SBR platform. Made from 17-4 H900 steel and coated in Nitride, it can handle any environment. The cap is bored out to a .30 Cal projectile and will work in both the Ranger 5 and the Ranger 7 silencer.