The Army had a number of M1897A5 guns, sufficient for the mass-production for such a weapon, and the M3 half-track was coming into production. After some debate, the Army decided to place M1897A5 guns on the M3 half-track chassis, which was designated the T12 GMC.
The military had a sufficient supply of M1897A5 firearms for mass production, and the M3 half-track vehicle was being manufactured. Following some discussion, the Army decided to integrate M1897A5 guns onto the M3 half-track chassis, which was subsequently designated as the T12 GMC.