I have a model 10-5 that has 6 inch heavy barrel marked national police supply , it is about the same diameter as a quarter and it has a bo-mar rail sight on top with adj. sights and the front sight has hoods on each side extreamly heavy rig. IT also came with a special holster to accomodate the large barrel, it is marked RENO- OKEECHOBEE, FLA. I would appreciate any input about the history of this revolver. thanks Geraldo