in 1844, but between 1843 and 1846, 3,000 M1843 carbines were also manufactured by Simeon North. Action The back several inches of the barrel (the chamber) is a separate piece that pivots upwards from the front for reloading, similar in concept to the later Norwegian kammerlader. In essence, the weapon was still loaded front to back, but without the need to ram the charge all the way from the muzzle, similar in concept to loading a cylinder of an early cap-and-ball (percussion) revolver. One could also think of it as similar to loading a short barreled, single shot muzzle-loading "horse pistol", which then hinges down behind an extra several feet of barrel, avoiding the need for extracting the long ram-rod from its underbarrel rings, rotating it so the ramming head faced the muzzle, ramming the charge down the barrel, extracting the rod, flipping it again, and then returning it to its holding rings. With the short chamber, a simple hand-held tool could be used to easily and quickly seat the bullet onto the charge. More importantly, as with all breechloaders (and muzzle-loaders, prior to the invention of the Minie ball), the fact that one didn't need to load through the whole barrel allowed for the use of rifling in a standard-issue front-line military weapon (as opposed to weapons issued in small numbers to elite troops such as sharpshooters). In order for rifling to work, the projectile must fit very snugly in the barrel, which makes it harder and slower to ram the bullet down the barrel. Once fired, black powder builds up thick fouling very quickly, which makes the gun even harder to load; a typical muzzle-loading rifle couldn't be fired more than 3–4 times before requiring cleaning, or the bullet would be impossible to force down the barrel on loading, even with the mallet typically issued to riflemen to aid in forcing the bullet through the rifling while loading after the first two shots. This fact is why soldiers were still issued smoothbore muskets firing loose-fitting round balls, long after the merits of rifling were known; rifles simply couldn't be loaded fast enough for use in open-field combat, even though they were far more effective shot-for-shot. The loose fit of a musket ball allowed for faster loading, even after fouling built up, but also made adding rifling useless, since it wouldn't work without a tight-fitting projectile. With a breech-loader,