We were playing British Grenadier the first time some years ago. Black Powder wasn't invented at that time.
My fellow Sven bought the rules on a wargame show in Germany and we gave the ruleset a try.
We like the rules. They are not fast playing but somehow they worked so, that they feel right.
It's realy difficult to explain. But I think the secret is that we are three players, who like the system, and so we play it again and again. Meanwhile we know the game mechanisms and so it's always great to game with Svens miniatures on his great gaming table.