When were cartridge conversions first available for old west revolvers such as Colts and Remingtons? I know many were popular after 1873, but when did they come into production?
The first Remington conversions were available in 1868. They were a five shot .46 cal. The Colt Thuer conversion (front loading tapered cartridge) also came about in 1868. The Colt Richards conversion of the 1860 were made from 1872-1878, the 1851/1861 navy conversion starting in 1873. The Richards-Mason conversions were manufactured in 1877-1878.
The Colt Long Cylinder Conversions of the 1860 Armies in .44 Henry RF were probably available as early as the first Remington Army conversions.
Bootsie
They started to become available as custom projects shortly after the War of Northern Aggression, and really started taking off by 1866-1868. Factories were turning out conversion cylinders as a standard item and gunsmiths made quite a good living converting existing revolvers to the newfangled cartridge configuration.
Remember, the Rollin-White patent was held by Smith and Wesson until 1869 and from 1866 to 1869, conversion manufacturers enjoyed a golden era of popularity.
Even after the expiration of the Rollin-White patent, conversions remained popular as ever, mainly because of the cost. An 1875 catalog lists a brand-new Colt 1873 SAA for $13.00. A Richard-Mason Colt conversion in .45LC or a similar Remington conversion costs roughly $6.00. During a time when the average hard working citizen made about $100.00 a year, that presents quite an option