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.
Although muzzleloading rifles may be found in .45-, .54-, and even .36- and .52 calibers, the most common hunting caliber is .50. The “half-inch†bore is the most flexible in terms of loads, has sufficient power potential for commonly hunted game, and offers the widest accessibility of support and maintenance equipment.
A large part of the reason for the change is the development of popular pellets (Pyrodex was first) manufactured in 50-, 30- and 20-grain capsule units.
For whitetail deer hunting, in-lines with a 1-turn-in-24 inches to 1-28 twist will deliver excellent performance with a 100-grain propellant charge and sabots in the 250- to 300-grain range. Conicals in the 300- to 385-grain range typically do very well with a similar powder charge.
A .50-caliber muzzleloader with a 1-32 to 1-38 twist rate should do well with the same sabots and conicals with a propellant charge in the 85- to 90-grain range.
A modern .54-caliber muzzleloader is almost universally manufactured with a 1-48 twist, although I have a still-serviceable 35-year-old side hammer gun in that caliber with a 1-turn-in-72 twist rate, which was good for patched round balls only. An 85- to 100-grain charge will effectively shoot .54-caliber sabots, conicals (try 425-grain bullets) and patched round balls with equal accuracy.
