PROMAG Colt AR-15 .223 Caliber 30 Round Magazine-Blued Steel The ProMag Colt AR-15 .223 Caliber 30 Round Magazine is a 30-round magazine that fits AR-15 .233 rifles. The magazine body is constructed of heat treated steel with a black oxide finish with an injection molded magazine follower. The magazine spring is formed from heat treated chrome silicon wire and is made in the USA.