This magazine is correctly marked "M16/M16A1 CAL 5.56mm Univeral INDS. DIV. Simmons Prec. PROD. INC. West Haven, CONN. USA." | These magazines are extremely rare because the US Government transitioned to 30rd Magazines in the early 1970s. Simmons was not apart of the original lineup for military contracts for 30rd magazines. The Company stopped producing military magazines in 1971. | This magazine is still in great shape and is a big part of American history from the Vietnam War - Post Vietnam war period.