[Swordmaker]

First of all, as a one time Colt Collector, it is NOT a Colt.

It MAY be a Harrington and Richardson, but I don't think so. H&Rs were mostly top-break. I think it might be a variation of an Iver Johnson .22 target pistol. I vaguely recall a revolver that looked like this that was sold by Sears and Roebuck around the turn of the 20th Century; they were made by Iver Johnson... and here is a sample of an Iver Johnson .22.

[Swordmaker]

Note the matching diamond checkering on both guns...

[Jaysun]

I just replied to Squantos on this same subject, so please see post 20 when you get a chance. I have an Iver Johnson that was ordered from Sears and Roebuck at the turn of the century. It's a .22 "Supershot", but as I explained to Squantos, this pistol is considerably smaller than any of the Iver Johnson's I've ever seen. It's very simplistic. For example, there is no "firing pin" in the traditional sense, it's built into the hammer on this gun. The "Scout Model" is unusual and keeps throwing me off.

[Jaysun]

Here's the pistol in question next to one of my Iver Johnsons. While it isn't the exact same model as the one that you pictured, the frames and cylinders are shaped the same. Maybe this will help.