Build 3: mine it, smelt it, shoot it
Ammo stopped being free. Iron veins and sulfur vents in the rock feed mining drills, conveyor lines carry the ore to blast furnaces, and a foundry turns it into steel rounds. The APU can mine too, with a laser. This build also lets bots play it: four strategies run headless on ShipGames, and their results are kept apart from real players' numbers.