Дробилка Serial No Rr marinosterlefotografo eu ruger single six serial Ruger Forum Oct 20 2017 · fuzzybonz You have a nice SingleSix there first because it was sold as a OM Magnum model no 22 LR cylinder and secondly because the D in your S N means it was a duplie serial number in other words Ruger screwed up and used the same s n on two guns so the second one got a