Grinning Man Entertainment have posted their free “Then Holler” American Civil War rules on their website.
From their announcement:
Thanks so much for the overwhelming support over the past couple of weeks. We’ve added a lot at our website.
The basic rules are now available for free download. They contain enough to model any conceivable infantry engagement in the American Civil War. Rules for cavalry and artillery will be fine-tuned and posted to the site over the next week.
We hope you enjoy the game. It’s written with 15mm miniatures in mind, with an inch representing about 50 yards, but most design work was done with paper and cardboard counters. Despite the scope of the rules you should be able to learn them in about 10 minutes.