I have a few suggestions: 1. Unguided rocket artillery, like an MRLS turret 2. A 50mm or 60mm cannon, it would fill a gap between not enough damage from a 30mm gun and total destruction from the Howitzer or the Abrams turret 3. Non moving , non gattling gun, gun mounts for .50 cal, 20mm, and 30mm 4. A ground to ground missile like an anti tank missile 5. IR smoke for ground vehicles to combat incoming missiles.