Jbanner, the single action/double action definitions may be counter intuitive, but here's how it was explained to me. With a single action, like your Ruger Single Six, the trigger performs one function. It releases the hammer which has been manually cocked. With a double action, the trigger performs two functions. It both raises (cocks) and releases the hammer. To further confuse the issue, many double action revolvers will also function in the single action mode, i.e., the hammer can be manually cocked and released by the trigger.