The Triplett & Scott Carbine was an American Civil War era repeating rifle, designed by Louis Triplett and William Scott. Only 5,000 or so Triplett & Scott carbines were produced by the end of conflict, by which time Triplett & Scott's manufacturers lost interest in the design.
The Triplett & Scott was a rather unusual piece during its era, as virtually all of its contemporaries (ie the Maynard Carbine or Merrill Carbine) were single shot firearms. The Triplett & Scott, on the otherhand, was a repeating rifle holding seven shots in the magazine. The design itself consisted of a two parts, where the entire barrel, breech etc. would be attached to the stock (and other components) via a revolving hinge, which allowed the barrel to be twisted clockwise in order to allow the spent cartridge to be ejected. When this cartridge was ejected the barrel would be twisted further towards clockwise, releasing a spring latch which loaded the next cartridge. The barrel was then twisted anti-clockwise, locking the barrel in position for firing.
This design required the magazine, tubular in design, to be mounted within the buttstock. This presented two problems: firstly that the magazine could not be removed, meaning the shooter would have to reload the magazine with each cartridge one at a time; and secondly this design severely weakened the buttstock. The area around the wrist of the stock was almost entirely taken up by the magazine, leaving little wood joining it to rest of the stock, often causing the stock to snap under little stress.
Otherwise the Triplett & Scott was rather uniform to any other carbine of the era, with a blued, five groove rifled barrel and basic iron sights. The action resembled the familiar percussion lock design, although it had been modified so that the hammer would strike a firing pin, meaning that the Triplett & Scott could use metallic rimfire cartridges instead of the more familiar paper cartridges.
The Triplett & Scott was one of the few American Civil War era firearms that used metallic cartridges. Specifically the Triplett & Scott fired the large calibre .56-50 Spencer cartridge, which had been developed for the Spencer carbine. Another unique feature of the Triplett & Scott was the seven round magazine, located in the stock.
The Triplett & Scott was a later comer to the American Civil War, so much so that the only troops to be issued with the carbine were home guard troops in Kentucky (whom protected supply lines). Despite the innovation in the design, the weaknesses the design created, particularly to the stock put its potential users off. These combined factors meant that the initial order of 5,000 firearms were delivered on the 1st May 1865, just over a month before the conflict ended.
This has meant that the Triplett & Scott, despite being one of the more innovative designs of the conflict, is not particularly sought after (even though surviving numbers are though to be in the tens). Modern day prices are around $1,500 on average.
http://www.19thcenturyweapons.com/308/tripscott.html - Image origin