He was originally a blacksmith by trade, but soon began to make pistols as well and his skill reached such a level of proficiency that he became famous in Scotland. These pistols used flintlock firing mechanisms, similar to those made by other manufacturers at that time. However, these weapons had certain features that made them completely different from weapons made anywhere else.
Unlike other manufacturers of weapons, Caddell used pattern-welding techniques to make his steel. These techniques were originally used 700 years earlier by the Vikings to manufacture their swords. This meant his steel was of a higher quality than many of his competitors.
During this period there was a shortage of suitable wood in Scotland used to make stocks for firearms, so instead Caddell made his weapons completely out of steel.
Since many of his customers were short-tempered Scottish Highlanders, Caddell's pistols featured no trigger guard or safety catch so enabling quicker firing. In addition there was a long steel ramrod stored under the barrel. Users would use this to push the ball (bullet) and gunpowder into the barrel, when loading the weapon. The butts of his pistols were shaped like a ram's horns or a flared heart-shaped piece. This gave them an artistic touch, but also made them easier to pull out quickly. The center ball shaped knob at the butt could be unscrewed out. The knob had a thin pricking pin at the end, which could be used to clean out the touch-hole of the flintlock firing mechanism. This made these weapons more suitable for rough conditions. Even though Caddell's pistols were more expensive than his competitors, their quality and reputation for reliability was so high that Highlanders saved up to buy his products in preference to other foreign manufacturers.
The factory founded by Thomas Caddell became a family business, carried on by five generations of this family (interestingly enough, the founder's son, grandson and great-grandson were all named Thomas Caddell as well!). Other pistol factories were also opened up in the area, many founded by people who had served as apprentices at the Caddell factory, such as Murdoch, Christie, Campbell, Macleod etc. Some of the pistols manufactured by these factories were heavily ornamented with elaborate engravings and inlays made of gold and silver and cost over 50 guineas and were proudly carried by nobility.
In 1745 the Highland army of Prince Charles Edward Stuart passed through Doune on its way south. The subsequent crushing of the '45 Uprising and the passing of the Disarmament Act signalled the end of the traditional market for firearms.
Today Thomas Caddell pistols fetch huge sums of money when appearing on the open market. The old factory has been restored with a plaque detailing its past. Located down an alleyway from the main street in Doune.