The George Washington government arranged for two state arsenals to be built and these became the Springfield Armory of Massachusetts and the Harpers Ferry Armory of West Virginia. Both became prolific gun-making facilities for their time in American firearms history and supplied many of the best known small arms featured in the American Civil War of 1861-1865. One of the contributions arising from both locations (as well as from private gun-makers) was the Springfield Model 1855 which was produced during the pre-war period from 1856 until 1860 and some 60,000 units were completed in all. Its availability made it a standard-issue weapon for both sides of the conflict and it was also the first standard-issue American rifle in .58 Minie ball, the revolutionary expanding, conically-shaped French bullet.
This particular gun was categorized as a "rifled musket" due to its internally rifled barrel and its musket origins (though by definition it was a rifle through-and-through). The long gun benefitted from using the newer Minie ball bullet of .58 caliber whereas previous American rifles were married to the .69 ball. The Minie was found to have better accuracy and retain its range and man-stopping capabilities when compared to the larger .69 ball round.
The gun featured a long-running wooden stock which incorporated the grip handle and shoulder support. The metalworks (lockplate) were concentrated at the rear of the weapon with the trigger unit underslung in the usual way. Three barrel bands were featured for strength and a ramrod was held under the barrel. This was a muzzle-loaded weapon so the ramrod was useful in ramming the powder and shot contents down the barrel towards the action. Sighting was by way of iron fittings over the receiver and at the muzzle end. Overall length became 56 inches with a barrel measuring 40 inches long.
Before the war, many armies were still reliant on smoothbore muskets which involved a barrel sans rifling. This meant that the ball bullet rattled its way down and out of the barrel with little accuracy to be had at range - as such massed formations of troops were used to increase lethality. Rifling soon changed all that as the revised, expanding conical bullet pressed firmly against the spiraling, ridged sides of the barrel assembly and a rotating action was imparted upon the outgoing bullet, allowing for more stability along the flight path of said bullet and therefore more inherent accuracy at range could be had.
In addition to smoothbore barrels, many firearms of the pre-war period were also developed around the flintlock system of operation which introduced a host of issues to the firing action - mainly environmental which could render any exposed gunpowder useless and lead to misfires. As such, the 300+ year old method of firearm action was being replaced by the percussion cap system which involved a better sealed action and a percussion cap fitted to a nipple outside of the action. The hammer actuated this cap which caused the needed spark to ignite the powder within the chamber. The resulting expanding forces then propelled the bullet out of the barrel at a considerable speed towards the aimed spot. The percussion system was less prone to weather and other environmental factors and soon replaced flintlocks in service - indeed, many flintlocks were simply modernized through a relatively simple process to take on the percussion cap system.
So the percussion cap system of operation, coupled to rifled barrels with new conical bullets, increased the lethality of the standard infantryman and it was this warfighter that was to be featured in the war between the "North and South".
The Springfield Model 1855, with all its modern qualities in place, allowed the rifleman to shoot up to three rounds-per-minute, another improvement over flintlocks. The bullet exited the barrel at about 1,100 feet-per-second and held an effective range out to 250 to 300 yards. Maximum range was well beyond that, though at a loss of accuracy, with 1,000 yards being possible. The rifle was still limited to single-shot firing so the shooter had to reload between shots - a major failing of many of the long guns of the Civil War. Additionally, the muzzle-loading process exposed the shooter to all manner of battlefield dangers, often requiring him to be standing. An added bayonet under the barrel also increased the length of this already lengthy gun and made wielding it in close quarters difficult. Nevertheless, bayonets were still highly valued on the battlefields of the American conflict though there were few bayonet charges recorded.
Another of the key changes to the Model 1855 arrived with the "Maynard Tape Primer" system. This system utilized an automatically feeding tape mechanism which contained a sequence of percussion caps "ready-to-fire" (as opposed to the shooter having to affix an individual cap to the action each time he fired). The tape was moved through management of the hammer assembly though individual percussion caps could still be affixed to the nipple in the usual fashion.
In practice, this tape system did not live up to its billing and misfires were common so unreliability remained high and many of the guns were eventually operated with individually-affixed percussion caps during the war. Guns also had their Maynard Tape Primer systems completely removed and this, by default, sped up - and lowered the cost of - per-unit production commitments. The changes eventually produced a revised designation in the Springfield "Model 1861" detailed elsewhere on this site. The Model 1861 found better success in-the-field due to improvements in the line.
The Springfield Model 1855 series saw first-combat in 1858 against Native American forces in the West. It was available in number at the start of the American Civil War and, since the rifle was produced at the Harpers Ferry location, it also made up the inventory of the Confederacy as the location was captured in 1861 and the related gun-making machinery relocated to better protected Confederate hubs in other states to continue to churn out this useful rifle during the war.