From their post:
S&R is a new skirmish game from Dadi&Piombo and covers the period from approximately 1700 to approximately 1900.
Two other supplements covering the French and Indian war and the New Zealand war are already available (free download from the blog).
The American Revolution, the Jacobite Rebellion, Darkest Africa, Zulu War, Boer War and Russo Turkish War supplements, all free, are on the workbench.
Smooth&Rifled is available as PDF at 9 euros at this page: http://www.dadiepiombo.com/smooth.html
Keep an eye on http://smooth-and-rifled.blogspot.com for updates and free lists.