The Mk103/38 was a late-war, four-gun installation of the Mk103 3cm gun from Rheinmetall Borsig. The Mk103 was an electrically fired, recoil and gas-operated automatic cannon designed to be used as a dual-purpose weapon against air and ground targets.

The Mk103 had a rate of fire of 280 rounds per minute using high explosive (HE) rounds, and 420 rounds per minute when firing Armor Piercing rounds.

The experimental Mk103/38 four-gun installation proved troublesome due to fact that the mount was originally designed for the smaller 2cm Flak 38, and heavy vibration took it's toll on both the equipment and the crew aiming the weapon.