Introduced in 2012 the Mil-Sport M4 Carbines became instant hits among customers looking for top quality AR-15 style rifles with forged aluminum receivers. Fine-tuned with many popular features these U.S.-built beauties perform perfectly right out of the box and are priced just right. Our Mil-Sports also include a magazine! - Forged Aluminum Upper Receiver - Billet Aluminum Lower Receiver - 7.5 Barrel - 7 Drop In Quad Rail - Standard Profile Picatinny Rail Gas Block - Includes One 30RD MAG - Chambered for 300 Blackout