Old West is a set of free wargames rules for wild west skirmishes.
The main rules file on the Internet Archive capture of the page is in Postscript format, so I converted it to a standard PDF. You can download it below.
Rules: 19th Century
Cold Steel Miniatures Rules for 1690 to 1850
Cold Steel is a set of free wargames rules for the period 1690 to 1950 offered by Historic Enterprises. The first release offers the basic rules, plus specific addendums for the Wars of Napoleon and the War of 1812. The nice thing about the rules is that they offer a flexible scale system, with each figure representing between 5 and 60 men. This should allow you to fight a wide variety of battles with the same rules set.
Crimean War Rules
Natholeon’s Empires has a set of free wargames rules for the Crimean War.
French Foreign Legion At Camerone Rules
The Wooden Hand of Captain Danjou – The French Foreign Legion at Camerone is a set of free wargames rules for refighting the “romantic” stand of the French Foreign Legion at Camerone during the Maximilian Adventure of 1861 – 1867.
Reasonable Brom
Reasonable Brom is a variant of Larry Brom’s standard rules for the 19th Century.