Excuse the back-to-backs, but I reconsidered the fighter/50-cal bit - the sandcasters work better.
The Adventure-7 Broadsword 6dT fighter is a short-range single-seat missile-armed fighter intended for limited duration flights (maximum 12 hours combat or 24 hours routine flight per High Guard). It lacks a bridge, channeling control functions through the computer with consequent reduction in weapons accuracy and defense for space combat - a disadvantage but not a major problem if it's engaging ship's boats or similar light craft. The fighter consists of a 1.08dT power plant, 1.02dT maneuver drive, 1.08dT fuel, a single 0.5dT crew seat, a 1dT model-1 computer, and a 1dT "turret", with 0.32dT remaining.
Lacking a crew cabin, the vessel can't be used for interplanetary flight or extended operations, but it's effective for its intended role as an orbital and close-air-support mercenary fighter with the single missile launcher launching 15cm tac-missiles (HEAP pen=48 at TL-12). Broadsword specs do not include sandcasters, but High Guard permits the craft to carry up to 2 sandcasters without needing additional gunners. Beyond improving combat survivability, the dual sandcasters could double as effective antipersonnel and point defense weapons (effective range: 500m./20/+8 with 40m wide danger space; long range 1000m/10/+6 with 80m danger space; extreme range 2000m/5/+4 with 120m danger space).
0.32 displacement tons of space is available. A variant of this model could mount a single course of armor at 0.24dT, giving it a Striker armor rating of 64 for ground combat purposes. The remaining space (0.08dT, or 1.08m^3) can be configured as a bomb bay for up to 10 100kg laser-guided CBM bomb (+10, contact pen = 24, burst = 200m, frag pen = 8 at TL12) with a laser carbine for the targeting role, further enhancing its ground support effectiveness, or to deliver a ton of supplies to the troops, the armored version being somewhat less vulnerable to ground fire than the cutter (or ship's boat).