This is Super Blackhawk, which means it is a .44 Mag. I own a Ruger .357 Mag Blackhawk, from 1965. This is called a 3-screw gun, and it looks like this one is also a 3-screw gun. This means that the gun may fire if dropped or banged, and so you should not carry a live round in the active chamber. There is a chance that the gun was improved/updated by Ruger, and if the transbar was perhaps installed, so you may want to ask if this has been done. I had mine 'fixed' about 10 years ago, so now I can safely carry a full loaded gun (all 6 rounds(.