ive read this idea on this site:
take a wood dowel rod and insert it into the bore all the way through the chamber. Then glue or epoxy a flawless brass case on the end of it. Pull it into the chamber and twist the rod. push it out, break the rod, then inspect the casing for a cut that circumvents the casing for an idea of where and how bad the chamber bur is. If its a major cut, call ruger.
"The very atmosphere of firearms anywhere and everywhere restrains evil interference - they deserve a place of honor with all that's good." -George Washington