The 50 Browning Machine Gun, sometimes known as the 50 BMG, is a 50 in (12.7 mm) caliber cartridge that was created for the M2 Browning heavy machine gun in the late 1910s and entered formal service in 1921. The machine gun was initially produced during World War I, and despite being cumbersome, the tank began to find its place on the battlefield—it was also resistant to most rifle and artillery shots.
The 50 BMG cartridge has a 290-gram capacity (19 g). The round is a scaled-up version of the 30-06 Springfield, but it has a case wall with a long taper to make feeding and extraction easier in different guns. This cartridge's rifling twist rate is 1 in 15 in (380 mm), with eight lands and grooves.
The 50 Browning Machine Gun is employed in anti-materiel rifles in addition to the M2 Browning heavy machine gun. There is a wide range of ammunition available, and match grade ammunition has boosted the use of 50 caliber rifles by allowing for more precise firing than lesser quality rounds. During WWII, the 50 BMG was principally utilized for anti-aircraft duties in the M2 Browning machine gun, both in its "light barrel" aircraft mount form and the "heavy barrel" (HB) version on ground vehicles.
Depending on the powder and bullet type, as well as the weapon from which it is shot, the 50 BMG round may create between 10,000 and 15,000 foot-pounds force (14,000 and 20,000 J). The 50 BMG's trajectory suffers less "drift" from cross-winds than smaller and lighter calibers due to the high ballistic coefficient of the bullet, making it an excellent option for high-powered sniper rifles.
The .500 Jeffery is a big-game rifle cartridge that first appeared around 1920, and was originally introduced by the August Schuler Company, a German firm, under the European designation "12,7x70 mm Schuler" or ".500 Schuler". It was renamed the .500 Jeffery so as to be more palatable to British hunters and sportsmen following World War One. When introduced the .500 Jeffery was the most powerful rifle cartridge in existence and remained so prior to World War II. The 505 Gibbs, introduced prior to it in 1911, has only recently been loaded to higher modern pressures, although still below, hence remaining less powerful.
When the .500 Jeffery was first introduced it was loaded to a velocity of 2,350 feet per second (720 m/s) topped off with a 535-grain bullet generating 6,560 ft·lbf (8,890 J) of muzzle energy, which makes it a pretty good hunting caliber generally where thick-skinned dangerous game occurs. Since then, reloading capabilities have advanced, being able to launch heavier bullets at higher velocities. Now with modern reloads, the .500 Jeffery can launch a 600-grain bullet at a muzzle velocity ranging from about 2,450 to 2,500 ft/s (750 to 760 m/s). max. generating 7,995 ft·lbf (10,840 J) to 8,100 ft·lbf (11,000 J). With the newer reloads, this made the .500 Jeffery the most powerful production cartridge in the world until the introduction of the .460 Weatherby Magnum.
The .500 Jeffery has had a few issues since its introduction. It has a rather short neck length that can make it difficult to seat bullets with a large sectional density. Also, it has a small shoulder. This is not usually an issue but since the .500 Jeffery also has a rebated rim, it makes it rather difficult to extract in extreme conditions. But like the 505 Gibbs, the .500 Jeffery is also still enjoying somewhat of a renaissance among American shooters and African Big Game hunters in the early 21st century, almost 100 years after their introduction. It’s known to be used on large games like elephants.
