The “straight breech” block design that first appeared on the New Model 1859 did help alleviate some of the gas leakage. The rifles and carbines built on through the Civil War with New Model 1863 and New Model 1865 markings generally reflect improvements to further reduce the escape of gases from a burning powder charge. Basically, these Sharps guns were all the same design, based on the New Model 1859.
The 115,000 rifles and carbines produced from 1859 to 1866 represented approximately 65 percent of the total number of Sharps breechloaders ever manufactured. No other official military arm of the Civil War went on to remain as popular with civilian shooters and hunters, not even the Remington rolling block rifles. While the latter went on to be produced in far greater numbers, the true rolling block action was not perfected until about 1866.
The Sharps dropping-block action lent itself well to making the transition from percussion ignition to handling the newly developed cartridges that evolved quickly following the end of the war. In fact, in 1867 the U.S. Government decided to convert or have converted a number of percussion military arms into metallic cartridge breechloaders. And the Sharps was one of the designs selected for conversion.
In all, the Sharps Rifle Manufacturing Company converted 31,098 carbines and 1,086 rifles to accept one or the other of the experimental 52-70 rimfire, 52-70 centerfire or 50-70 centerfire cartridges. All were fitted with new breechblocks with firing pins and an extractor. Those converted to the 50-70 cartridge also required soldering a new 50-caliber barrel liner in place. In 1870, Springfield Armory additionally converted about 1,300 more Sharps rifles and carbines to the newly designated 50-70 Government cartridge.
From 1869 to 1871, the Sharps Rifle Manufacturing Company produced their first entirely “new made” cartridge model – the Sharps New Model 1869. What really set this model apart from the converted percussion military models was the much cleaner looking lockplate, which had been trimmed of the pellet priming system that gave the Civil War-era percussion models a “high hump” contour. The lines of the new lockplate were a lot cleaner.
In all, only about 1,000 New Model 1869 carbines and rifles were produced, chambered for early cartridges like the 44-77 Sharps and 50-70 Government. That production also included about 200 sporting rifles that would set the stage for the famous Model 1874 Rifle, which became the favored gun of the professional buffalo hunter.