Mike Willegal offers A Perfect Sheet of Flame, a set of free wargames rules for gaming the Amerian Civil War. Mike writes that this is the fourth version of his Iron Brigade system:
This forth version has a major revamping of the game mechanics. Gone is the sequential alternate movement system. In place is a order driven simatanious movement system. Orders must be generated by officers and isolated units may only execute their orders after a delay. Gone is the need for the results tables. In place of that, the player must perform some very simple math (adding up the sum a of a number of dice) followed by a simple divide. The result is intended to be a much more exciting, and fast moving game. The old system of tying morale to fire combat remains, though in an altered format. The overall effect of combat should be similar to the previous version, with a bit more luck thrown in. This should average out quite quickly in battle, as I have studied probilities of sum of a number of dice quite carefully in coming up with this system.