Ah, a Model of 1909! One of my favorites. The M1909 is the rarest of all military Colt cartridge handguns. Murphy in his New Service book reports that the number of Models 1909 may be a low as 13,000 and no higher that 18,303. That is rare by other military cartridge revolver standards, and even by commercial standards. The high-polish commercial grade finish on a prime example is something to behold. The pictured gun does not exhibit the high polish finish, but perhaps the finish has been dulled by wear and corrosion rather than a refinish since the edges seem good and sharp, and the sideplate fit is fine, areas often damaged by a typical refinish.
The M1909 was the last military revolver before the semi-automatic pistol took over. It is chambered for one of the most famous cartridges ever. After the M1847 Walker, it is the most powerful American military handgun ever (along with the SAA of course). It is the rarest cartridge military revolver. A good example is desirable for any Colt collection. Value is dependent on condition. A worn but original example will generally sell from $600 and up as condition improves.