The Harper’s ferry horse pistol was truly a remarkable handgun in its day. In 1855 single shot handguns were still common, even though Colt was developing their line of revolver based handguns, the earliest being the Paterson in 1836. Many other manufactures were also developing revolvers as well. Early revolvers were not fully accepted by the public or even the U.S. military at the time. Many reasons are apparent, but the true reasons may have been simply that they were too futuristic and modern to be trusted. Revolvers would certainly play a large part in a very few short years with the coming of the civil war.
The Model 1855 Horse Pistol was a hard-hitting powerful weapon. It achieved this with remarkable success. In 1805, Harper’s Ferry created the model 1805, flintlock military handgun. The Horse pistol was to closely follow its earlier design with modern improvements. The biggest improvement would be the conversion from flint to cap ignition. Caps were a marked improvement for any firearm in 1855. The cap was quick to install, was not affected by water to the degree that flint was, and the cap was almost always assured to fire when struck by the hammer. The barrel was also lengthened to 12 inches, which would have improved the guns accuracy and power.
Many names have been attributed to the Horse pistol, some of which were Dragoon Pistol, Model 1855, and the Pistol carbine model 1855.
Designed in 1855 for the United States mounted rifles the gun was to be carried on the side of the horse in a holster. It was said that the soldier would carry one pistol on each side of his horse. The model 1855 provided so much power, it was possible for the soldier to shoot at the horse of an enemy, thereby taking his victim out of the fight.
The handgun was a .58 caliber single shot, and fired a 525-625 grain Minie bullet, or 278-grain ball. 40 or even 50 grains of powder would be loaded in the pistol. This combination of large bullet and high powder loads would certainly make a most formidable weapon. For a comparison, the Colt and Remington revolvers would have a .44 bore and a 143-grain ball, with 20-30 grains of powder loaded. The Horse pistol fired a projectile twice as heavy by weight, and it had more powder loaded as well. It should also be noted that not all revolvers were in .44 caliber, many of them were smaller being .31 or .36 Navy caliber.
The Horse pistol had a rifled barrel almost 12 " long. The barrel was round at the end and octagonal at the breech. Rifling served to greatly improve the accuracy of any firearm by causing the projectile to spin as it left the barrel.
Accuracy of the Horse pistol would have been on a par with the revolvers of the day, easily capable of hitting a man or horse at 25 yards. Pistols and revolvers were never intended for long range shooting, but with the addition of rifling at least a soldier would know that his bullet would go where he wanted it to. I have not fired the Horse pistol, but I have had occasion to fire an 1861 Colt model and an 1858 Remington. It is not difficult to hit a tin can from 50 feet away, and at times, I was able to hit tin cans 150 feet away. It should be noted that these handguns had shorter barrel lengths then the 12-inch Horse pistol. If that accuracy is not good enough to hit something as large as a horse, which is what the Horse pistol was intended for, the soldier could attach an additional shoulder stock.
This stock mounted to the pistol grip of the gun, turning the Horse Pistol into a short barreled rifle. Accuracy would be greatly improved, because it would be much easier to hold the pistol to the shoulder and sight along its barrel as if shooting a conventional rifle. The optional shoulder stock also had a small lanyard ring in the back of it. A soldier could then use a strap connected to a front lanyard ring on the pistol barrel and the aft ring on the optional stock. This strap would serve to make it easier to carry the Pistol/Rifle as one unit.
Rear adjustable swivel sights were also provided on the Horse Pistol. The rear sight was a small L shaped piece of metal, with a hinge at the corner of the L. This was mounted on the back of the pistol. A shooter could rotate the L so that in effect the foot of the L or the longer side of the L would face upwards. This was a very simple but effective approach to changing sight range for long distance shooting. This adjustment certainly would be handy when using the optional shoulder stock.
Loading of the pistol was typical for single shot handguns and rifles of the period. An interesting feature of the Harper’s ferry horse pistol was an attached swivel, loading rod. This loading rod was mounted inside a hinged swivel attached to the front of the barrel. A shooter could slide the rod partially out of its under barrel holder, rotate the swivel around, and then plunge the rod down the barrel to seat the projectile. This would be a very useful battlefield addition to the weapon. Reloading from horseback would not be quite so difficult if you did not have to worry about dropping the ramrod.
The horse pistol was used by the U.S. Mounted Cavalry, and would primarily have been used in the western United States. The pistol would have been designed for Indian fighting and battles with Mexico. With the advent of the Civil War in 1861, there would still have been many of these Horse pistols issued to U.S. Troops. This weapon was designed and issued just before the war broke out, but it’s probable it was still carried by Union mounted cavalry.
The Harper’s Ferry Horse Pistol was designed almost 150 years ago, and yet ballistics tests with modern reproductions place this pistol as being very close to a modern .44 magnum. Whether the original was more powerful then today’s .44 magnum does not matter, the Harper’s Ferry Horse Pistol was a magnum in its day.