This is a Colt Officers Model Target .22 LR revolver. The serial number is 50XXX, which the online Colt serial number database puts at 1948.
The revolver locks up fairly tight, but you can get a little bit of counter clock wise rotation out of it at full lock up. The revolver carries up fine when cocked at normal speed, but will occasionally not carry up when cocked slowly. I have had the occasional light strike with it. There is no apparent damage to the hammer and the mainspring tension seems ok, so it may have been the bulk 22 ammo.
I do not know if the grips are original to the revolver, but the inside of one of the panel grips has a little bit of damage where the locator pin fits in. The grips seem to stay in place pretty well when tightened, but I shot this revolver with Herrett target grips. The target grips are also included.