ピカティニー・レール
The SIG 522 Classic has a standard polymer handguard, M1913 Picatinny rail on top of the receiver, and folding and telescoping stock. A flash hider modeled after the M16-A2 style "Bird Cage" flash suppressor is installed. Options include SIG Sauer iron sights and a SIG-branded mini red dot sight that mounts on top of the Picatinny rail. Barrel length is 16.6 inches, and weight is 6 lb, 6oz.