Senior Member

Colt didn't make a swing-out cylinder single action revolver.
Possibly you have a double action revolver in which the double action feature is disabled.
The two swing-out cylinder revolvers in .41 Colt that Colt did make were the Colt New Army & Navy, and the Colt Army Special.
The New Army & Navy was made as both a US military issue revolver and a commercial model. Only the commercial models were chambered in .41 Colt.
These were first made in 1889 and were upgraded as the models 1892, 1894, 1895, 1896, 1901, and 1903.
These were the world's first swing-out cylinder double action revolver.
The action is notoriously complicated and fragile, and it's common for them not to work correctly.
These revolvers were shipped with hard black rubber (Gutta Percha) grips with molded in checkering and Colt logos.
The Colt Pony logo is on the left side.
These were made in bright nickel, but if the lettering is faint under the nickel, it's been refinished.
The second model Colt made in .41 Colt was the Army Special. This was made from 1908 to 1927, when Colt renamed it as the Official Police and continued making it up until 1969. The Army Special was a commercial model only.
All later Colt medium framed revolvers like the Trooper and Python were based on the Army Special.
Best guess is, you have one or the other in which the action is damaged and the double action feature isn't working.
Here's some pictures of the two types.
The Colt New Army & Navy: The actual serial number is stamped in two lines on the butt. The other numbers are factory assembly numbers.
Colt, New Army, .41 cal. (U 3828) c : Revolvers at GunBroker.com
The Colt Army Special. The same gun was made as the Official Police after 1927.
Colt Army Special .41LC Double Action Revolver : Revolvers at GunBroker.com
From the serial number of your gun, 71646, you have a Colt New Army & Navy, Model 1896.
The numbers that year started at 68000 and ended around 76999 by the end of the year.
It sounds like it was nickel plated after it left the factory, and the action is broken, limiting it to single action only.
These guns have to be in pretty good condition to be worth much. One with a damaged action and a non-original finish would probably be worth something around $200 at best, if not less.