"Introducing the world's first piston-driven rimfire AR: the Franklin Armory F17-X Semi-Auto Rimfire Rifle. Chambered in the flat-shooting .17 Winchester Super Magnum, the F17-X is a highly accurate option for pest control and more. Unlike direct impingement systems that spray carbon and dirty gas back into the action, gas piston systems run cooler and cleaner and require far less maintenance. The piston system automatically adjusts for suppressed or unsuppressed loads no adjustment needed and it functions with most suppressors. The 16"" barrel features the common ½""-28 thread pitch, so it's ideal for use with a suppressor, and comes from the factory with an Aura muzzle brake. The handguard features an integrated hand stop and has M-LOK slots for accessories. Other features include a B5 Bravo stock, custom-tuned trigger, and low-profile gas block. Gas piston system runs cooler and cleaner Automatically adjusts for suppressed and unsuppressed loads Low-profile gas block 16"" barrel with ½""-28 threads Aura muzzle brake 15"" M-LOK handguard with hand stop Custom-tuned trigger B5 Bravo stock"