In 1871, Mauser introduced the 43 Mauser for chambering in its revolutionary Model of 1871 bolt-action rifle. These guns were converted in 1884 into tubular-magazine repeaters featuring a magazine cut-off and several other important battle-rifle features. The original 43 Mauser load launched paper-patched bullets of 0.446-inch diameter and 386-grains weight using 88-grains of blackpowder to generate 1430-fps. This far outclassed the various Military cartridges then standardized and many that would follow. I own and use a fine example of the M71/84, 43 Mauser, a gift from my friend, Jim Williamson, so I know what this rifle can do. Performance and long-range accuracy of loads duplicating the original Military load are impressive. Using a heavier bullet and smokeless, loaded to duplicate what blackpowder would do with that bullet and with entirely safe pressure, using Andy Tuttle’s 71/84, we made hits on the official Friends of Billy Dixon target. This target is composed of the silhouettes of three riders on horseback. It is 1538 yards from the shooting line. We managed this using the original sights, which introduce significant sighting limitations. While that ladder rear sight allows for plenty of elevation adjustment to get on target, resolution of the detents moves impact about 20 feet vertically from one notch to the next at that distance. There is no mechanism to correct for windage or bullet drift. So, it was necessary to aim well off target to make hits. One of us made two offhand hits in a row after establishing an aiming point. These guns and this cartridge are amazing. Comparing this rifle to the Trapdoor Springfield is akin to comparing a Model-T to a Ferrari. Mauser later necked-down the 11×60mmR to use a 9.5mm bullet but that was a short-lived project because Mauser was already realizing something far better was possible. Still, the M71 was Mauser’s first significant foray into the turn-bolt action design and can be viewed as the logical progenitor of the modern bolt-action rifle. Original blackpowder loads probably generated about 25,000 psi and it seems prudent to keep modern loads used in original rifles to that pressure level or below. Such loads with the right bullet are entirely capable for big-game hunting of all but the largest and most dangerous of species. As with all cartridges used in guns with a tubular magazine, a properly applied crimp can smooth and ease chambering and a crimp is critical to lock the case mouth into the cannelure and thereby prevent recoil and chambering forces from driving the bullet into the case. In some instances, a roll crimp might be the best option But the Lee Factory Crimp Die usually does a better job and the crimp it applies will not damage a cast bullet as chamber pressure drives that from the case.