By the time the Civil War ended, there was no doubt that the self-contained metallic cartridge was the wave of the future. With the successful, widespread use of the Spencer repeater as well as more limited employment of other arms, such as the Henry and Joslyn, the message was clear: The percussion muzzleloader and breechloader were doomed.
Other countries were also in the process of switching over, and the United States didn't want to be left behind. With hundreds of thousands of rifle-muskets on hand, the obvious money-saving solution was to try to find some way to convert these arms to handle the more modern ignition system.
While some excellent newly made arms were submitted for testing, the prudent thing to do was to adopt a method that would be able to make use of the resources at hand.
The Yankees were not alone in this, and nations such as Britain, with its Snider conversion, and France, which adopted some muzzleloading muskets and carbines to the Tabatier system and Chassepot bolt-actions to handle the 11mm Gras cartridge, were also going in the same direction.
Uncle Sam tried many different arrangements before settling on one devised by Springfield Armory's master armorer, Erskine S. Allin. The new design was slick, and an additional benefit was that Allin was a government employee, which meant the war department would not have to pay royalties on the design.
Basically, the system involved a breechblock that was attached to the top of the altered rifle-musket barrel. To open it, one half-cocked the hammer and pushed upward on a thumb latch to unlock the block. It would then be rotated forward to expose the chamber for the insertion of a round.
The block was then closed, the hammer put on full-cock, and the rifle aimed and fired. Upon reopening the block, a rather complicated rack-and-pinion extractor ejected the spent case. Fast, slick and easy.
As well as being relatively efficient, the conversion allowed the maximum use of original parts. Allin explained: "It is particularly adapted to the alteration of the Springfield rifle-musket (or any other), as it can be done without changing the features of the musket or without throwing away any of its parts. All that is necessary is to cut away the barrel on the top at the breech and add the block and shell extractor, cut the recess in the breech-screw and modify the hammer. All other parts remain the same."
These were honeyed words to penurious ordnance officials. The system was adopted in 1865, chambering a .58-caliber copper rimfire cartridge that approximated the ballistics of the original muzzleloader's paper cartridge. Because of this, even the rear sight didn't have to be changed.
Nicknamed the "needle gun" due to its long firing pin, some 5,000 of these Model 1865s were altered at Springfield before it was decided that some alterations in the mechanism and a reduction in caliber were warranted to further improve the gun's performance.
The original muzzleloading barrels were sleeved with a liner of .50 caliber to handle a new centerfire cartridge with a 450-grain lead bullet backed by 70 grains of black powder. This loading upped the velocity by 100 fps (1,260 fps) over that of the .58 rimfire and gave greater range and accuracy, though the muzzle energy was about the same (1,488 ft-lbs).
A lighter carbine load featuring a 400-grain bullet and 45 to 50 grains of black powder was also issued, and, as might be expected, the velocity and muzzle energy were somewhat reduced. Too, the old rack-and-pinion extractor was found to be lacking, and a new ejector, which involved a small spring-loaded stud set in the breech just behind the chamber, was adopted. The block itself was also slightly modified by employing coil springs for both the firing pin and latch.
Dubbed the Model 1866, 25,000 of these rifles were turned out at Springfield using Model 1863 rifle-muskets as platforms. In 1867 a shorter Cadet Rifle appeared but still no cavalry carbines — that role being handled by the thousands of Spencer repeaters still in the system and Sharps percussion carbines converted to .50-70.
Even though the 1866 was considered a successful arm, some modifications were deemed to be in order. The extractor still left something to be desired, and a new version was designed that involved a spring-loaded claw set into the receiver at the hinge of the breechblock. It was decided to shorten the gun's barrel and to adopt an en bloc receiver that could be screwed onto the rear of the barrel. Other mods involved a new long-range rear sight and larger cam latch.
In 1870 the first Springfield Trapdoor carbine version of the Allin conversion appeared. It, too, used bits and pieces of Civil War muskets, but the barrel was shortened to 22 inches, the half stock fitted with only a single barrelband and a bar and ring attached to the left side of the stock opposite the lock to enable the use of a carbine sling. Only 341 of these guns were made, making them among the rarest and most desirable of U.S. martial arms today.
Even during the heyday of the .50-70, it was recognized that .45 caliber was ballistically a better choice. Most Europeans were adopting "small-bore" .45 or 11mm loads, and it was finally decided that Uncle Sam should follow suit.
In 1873, a new model of Springfield Trapdoor carbine (so named because of the appearance of the breechblock) was introduced. Unlike its predecessors, it was not made from altered muskets but was fabricated completely from new. Also unlike the earlier guns, it was not finished bright but had blued metal parts with a case-hardened tang and breech and black oil-quenched breechblock.
Many of the parts were the same as those of the 1870 models, so Springfield was able to use some of the tooling for components on the older guns. The gun was offered in rifle, cadet rifle and carbine versions.
The .45-caliber cartridge, for which the guns were chambered, employed the Benet internal priming system and a drawn case with heavy copper content. Bullet weight was 405 grains, and the powder charge was 70 grains for the rifle (muzzle velocity 1,350 fps, muzzle energy 1,590 ft-lbs) and 55 grains for the more diminutive carbine.
In 1882 a 500-grain bullet was adopted for the infantry rifle. At the same time, the Benet internal priming was replaced with the Boxer external style.
The Springfield Trapdoor carbine itself was a very handy, attractive weapon. With its 22-inch barrel, it resembled the 1870 in many details but incorporated a stacking swivel on the front band. The rear sight was graduated from 400 to 1,300 yards.
Interestingly enough, the rifle's sights were graduated only to 1,200 yards, giving rise to the legend that the carbine was more accurate than the rifle. The simple fact is, because of the carbine's shorter barrel, the sight radius is different, making the graduations on the leaf closer together. Thus, it's possible to squeeze another 100-yard step onto the carbine sight.
Though delivery of the 1873s was slow, by the mid-1870s most of the regulars had been issued with them. Generally speaking, the soldiers liked their new arms, and despite limited opportunities for target practice (marksmanship training didn't really become a priority until the 1880s), they became quite proficient with them.
The men of Lt. Col. George A. Custer's famed 7th Cavalry were carrying Model 1873 Springfield Trapdoor carbines at the Battle of the Little Big Horn in 1876. After the battle, it was claimed that many of the soldiers' carbines jammed because the sharp extractor finger was tearing away the heads of the soft cartridge-case base, necessitating the men to try to pry the stuck shells out with their knives.
Recent forensics have shown that this did take place in some circumstances, but the extent to which it affected the battle is conjecture. There is good reason to believe that the carbine was actually used as something of a scapegoat to deflect attention from Custer's faulty handling of the battle and the defeat of modern troops by the Indians.
In 1877, the Springfield Trapdoor carbines again underwent some alterations. The carbine butts were fitted with traps that held a jointed cleaning rod and broken shell extractor. The older "low arch" breech was replaced with a breechblock with a more curved inner configuration, and modifications such as the elimination of the firing-pin spring and other configurational alterations were made.
Even though the guns were different from their parents, they were still marked "Model 1873." It might be noted that many Model 73s had very deep stampings, which made the "3" look like an "8," leading some collectors to think there actually was a Model 1878 Trapdoor. Such is not the case.
In 1879, the guns were again given a makeover. The carbine stacking swivel was eliminated, the receiver made thicker, and depending upon when the gun was made (180,000 were turned out between 1879 and 1885), they were fitted with ribbed triggers. Though considerably different from the earlier versions, these were still considered Model 1873s by the government and are so marked.
The Trapdoor rifles, carbines and other variants continued to be issued and carried right up to the turn of the century, and modifications, such as different sights, ramrod bayonets, etc., popped up from time to time.
The Trapdoor's last moment of glory was during the Spanish-American War when, in the hands of volunteers, it fought side by side with the modern smokeless-powder Krag-Jorgensen repeating bolt action.
I have several Trapdoors in my collection, both rifles and carbines, and have fired them for years, using proper modern smokeless loads and replicated period blackpowder cartridges. Even though it had been perfected, the Allin action is still not the strongest single-shot ever made, and, if you have an original Trapdoor, first take it to a qualified gunsmith for a going-over and then never fire the gun with loads exceeding original chamber pressures of around 25,000 psi.
That being said, I have found the Trapdoor to be one of the most reliable and accurate military rifles of its type. In shooting comparisons with the French Gras, British Martini-Henry, German 1871 Mauser, Austrian Werndl and Model 1870 Remington Rolling Block, of the batch only the rolling block is as accurate and the Martini-Henry as fast to load.
While naturally the rifles are more accurate than the carbines, for sheer shooting fun, I'll take my 1879 carbine over the lot of them. It's handy, light, responsive and as accurate as it has to be for the uses for which it was originally intended.
The buckhorn rear sight is not as technologically advanced as the later multi-adjustable Buffington, but it allows for rapid target acquisition and is simple and easy to use. To my mind, the 1879 is the ne plus ultra of the Trapdoor carbines.