Black West is a simple set of free wargames rules for skirmishes in the Old West.
Here are some paper figures of cowboys for your 28mm wild west games.
D6 Shooters is a solo Old West Campaign game. The format could be adapted to a wide variety of periods and settings.
The d6 Shooters are a famous Old West posse, and you are their leader. In this solitaire Print-and-Play series, you will lead your posse on several adventures and missions, using a Yahtzee-style dice system to gain resources, movement and perform other important actions. There is always danger near, and your journeys will be very challenging to complete, but there is also the potential for great reward with untapped gold deposits among the California lands where you travel.
The Napnuts’ Chew Boon Longe has a set of free wargames rules for western gunfights.
Dark City Games’ Legends of the Untamed West is a tactical RPG for the 1800s American West. The system is based on the wonderful Fantasy Trip system that originally was published in the micro games format. If you’re familiar with the Fantasy Trip, you know that it makes for just as good a miniatures system as an RPG.