8x57 JRS

Shortly after Germany adopted what is now commonly known as the 8mm Mauser, in 1888, Mauser introduced a rimmed version of that case, specifically for use in double rifles and combination guns. Originally, these two cartridges differed only in rim design. Amazingly, the "J" in the name originated with confusion over the word "Infanterie" found in German documents describing the military version of this cartridge. English speaking translators mistook the Gothic stylized "I" for a "J". (This interesting situation is discussed in some detail in recent editions of Cartridges of the World.) This letter has no significance as to proper bullet size. In 1905, the German army switched from a 226-grain, 0.318-inch, round-nosed bullet to a 154-grain, 0.323-inch, spitzer – grooves of all existing military 8x57 J barrels were deepened, to extend useful barrel life. The "S" in the designation stands for "Spitzer" and also indicates that the barrel was either originally made for, or was altered to use, 0.323-inch bullets. It is rare to find any rifle in use that is barreled for the original 0.318-inch bullet diameter; however, many good combination guns that were made for the original 8x57 JR are still around, so this is possible. To further complicate matters, many breach-break guns have only bullet diameter (8.2mm) stamped on the barrel, despite the fact that many distinct 8mm cartridges, using bullets of various diameters and cases of all sizes and shapes, were chambered over the years. If one has any doubt, please have a qualified gunsmith verify the correct chambering before attempting to fire any such gun with any cartridge from any source. The 8x57 JRS is a flexible and powerful cartridge duplicating 30-06 performance. Hence, many double rifles and combination guns are still chambered in 8x57 JRS every year. However, to assure smooth extraction and to avoid
overstressing these generally weaker actions, pressure should be kept low.