(1) Factory Swiss SIG 552 barrel in .223 in used good to very good condition. Barrel is threaded in 14mm X 1.0 LH thread pitch. Can be used as a spare for your swiss 551/552/553. This is a rare barrel and out of production. Note that Swiss SIG 551 / 552 / 553 barrels do not fit sig556 trunnion due to different thread pattern. Stock photo. Note this barrel is under 16" so ALL NFA RULES APPLY.