6+ is a fairly radical variation on the Horse & Musket rules from Neil Thomas' One-Hour Wargames. Most deviant indeed, owing to the fact that they dispense with dice rolling or randomization of any sort as an in-game mechanic. My aim was to arrive at a ruleset that harkens back to the dawn of wargaming history. I think of 6+ as an update on H.G.W.'s Little Wars.
[1] The SixPlus Napoleonic Blog