I bet the date is earlier than the 1850s, for the Hall breech-loaded, patented in 1811, was officially adopted as the 1st breech-loading rifle ever issued to US troops in
1819, with the first models issued as flintlock ignition. I have the 2 books on the Hall breech-loader and I'd bet that in those books,
that contain the official records of the arms trials, that the terms muzzle-loader and breech-loader are both used.
Synopsis: "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, a tight-fitting projectile can be used, as it doesn't have to be forced down the barrel, which allows the use of rifling as well as a fast rate of fire. This fact means that even a
breech-loader that only achieved the same rate of fire as a
muzzle-loading musket would still be superior to the musket, as the
breech-loader could be rifled and the musket couldn't, although in fact,
breech-loaders generally also had a greater rate of fire."
They also misspelled Sharps.
