One of the earliest guncad designs to be released to the world, the Cuomo Mag is a pre-Liberator design developed by Defense Distributed and released in January 2013. It is the first printable magazine ever developed.
This design provides for a standard 30-round capacity AR-15 magazine. All parts are printable except for the magazine spring. A “coupler” is provided that allows the magazine to be built using either a standard “rectangular” magazine spring, or a round “hardware” spring.
This magazine design spawned several descendants, such as IvanTheTroll’s 100% DIY magazine. Since superseded by other novel designs such as the Waffle Magazine, the Cuomo Mag remains available for historic purposes.