.243 Winchester

The .243 Winchester is a very popular sporting rifle round. It is very effective for deer hunting and long range varmint shooting. It uses what is basically a .308 cartridge case necked-down to accept a .244 in/6 mm bullet. The .243 is well known for its accuracy, very flat trajectory, and relatively mild recoil compared to other deer cartridges.

History
This cartridge was first introduced in 1955 for Winchester Repeating Arms Company's Model 70 bolt-action sporting rifle, and it quickly gained popularity among sportsmen worldwide. Even Winchester's chief competitor, Remington, was quick to chamber rifles for the .243 round, and all mass-market riflemakers have followed suit. Many companies offer a selection of rifle models chambered in .243 Win.

Since the enactment of the 1963 Deer Act in Great Britain, which stipulated a minimum bullet diameter of .240 in together with minimum levels of muzzle velocity and bullet energy, the .243 Win. has been perceived by UK sportsmen as the "entry level" calibre for legal deer-stalking; and since the 1960s the .243 has been by far the most widely used calibre for shooting small and woodland deer in the UK.

In a non-sporting, non-civilian context, bolt-action rifles chambered for the .243 Win. were utilized by the Los Angeles Police Department's Special Weapons And Tactics (SWAT) unit during its early years.

P. O. Ackley created an Improved version of this cartridge called the .243 Winchester Improved (Ackley). Like other Improved cartridges, this created a steeper shoulder and blew the sides out, plus slightly lengthens the case, giving about 10% more powder capacity, and some small improvement in velocity.

Performance
The .243 Winchester produces a velocity of 2960 feet (902.21 m) per second with a 100 grain (6.8 gram) projectile from a 24-inch barrel. Commercially loaded .243 ammunition is available with bullet weight ranging from 55 grains (3.6 g) up to 105 grains (6.8 g), typical use being with bullets of c. 75 - 90 grains (6 g).

The .243 has gained very substantial popularity in the international hunting world, and commercially loaded ammunition is easy to find in almost any gunshop. Along with the .270 Winchester, the .308 Winchester and .30-'06, it is amongst the most popular and widely available of all centrefire cartridges. The .243 is a popular and successful choice for all but the very largest deer, small to medium sized antelope, and for varmint hunting.

In the United States, the cartridge is used extensively in varmint hunting as well as larger deer-sized game. It's also used with good effect in competitions out to 1,000 yards (1,000 m).

The .243 Winchester is a Delta L problem cartridge, meaning it can present unexpected chambering and/or feeding problems. The Delta L problem article explains this problem in more detail.