.243 Winchester

.243 Winchester
A .243 Winchester cartridge (middle) next to a .223 Remington (left) and .308 Winchester (right)
Type	Rifle
Place of origin	United States
Production history
Designer	Winchester
Designed	1952–1955
Manufacturer	Winchester
Produced	1955–present
Variants	.243 Winchester Improved (Ackley)
Specifications
Parent case	.308 Winchester
Case type	Bottlenecked
Bullet diameter	.243 in (6.2 mm)
Land diameter	.237 in (6.0 mm)
Neck diameter	.276 in (7.0 mm)
Shoulder diameter	.454 in (11.5 mm)
Base diameter	.471 in (12.0 mm)
Rim diameter	.473 in (12.0 mm)
Case length	2.045 in (51.9 mm)
Overall length	2.7098 in (68.83 mm)
Case capacity	53.7–54.8
Rifling twist	1-10 in (250 mm) to 1-8 in (200 mm)
Primer type	Large Rifle
Maximum pressure (C.I.P.)	60,191 psi (415.00 MPa)
Maximum pressure (SAAMI)	60,000 psi (410 MPa)
Ballistic performance
Bullet mass/type Velocity Energy 58 gr (3.8 g) V-MAX 3,925 ft/s (1,196 m/s) 1,984 ft⋅lbf (2,690 J) 80 gr (5.2 g) TTSX 3,350 ft/s (1,020 m/s) 1,994 ft⋅lbf (2,704 J) 85 gr (5.5 g) TSX 3,200 ft/s (980 m/s) 1,933 ft⋅lbf (2,621 J) 95 gr (6.2 g) SP 2,980 ft/s (910 m/s) 1,873 ft⋅lbf (2,539 J) 100 gr (6.5 g) BTSP 2,960 ft/s (900 m/s) 1,945 ft⋅lbf (2,637 J)
Test barrel length: 24 in (610 mm) Source(s): Barnes, Federal, Hornady factory specifications, AccurateShooter.com[1]

The .243 Winchester (6×52mm) is a popular sporting rifle cartridge. Developed as a versatile short action cartridge to hunt both medium game and small game alike, it "took whitetail hunting by storm"^[2] when introduced in 1955, and remains one of the most popular whitetail deer cartridges. It is also commonly used for harvesting blacktail deer, pronghorns and mule deer with heavier rounds, and is equally suited to varmint hunting with lighter rounds. The .243 is based on a necked down .308 Winchester, introduced only three years earlier. Expanding monolithic copper bullets of approximately 80^[3] to 85^[4][5] grains or traditional lead rounds of 90 to 105 grains with controlled expansion designs are best suited for hunting medium game, while lighter rounds are intended for varmints.^[6][7]

In at least ten U.S. states^[8] and the United Kingdom,^[9] the .243 or similar cartridges are the smallest bore cartridges that are legal for hunting deer; this has been revised in the UK to allow Muntjac and Chinese Water Deer to be taken with .22 (5.56mm) chambered weapons.^[10] The cartridge can be extremely accurate to 300 yards (270 m) and beyond, but may not retain enough terminal energy to reliably drop medium game at that distance.^[4][11][12] Highly experienced hunters use the .243 Winchester to routinely drop bucks up to 250 pounds (110 kg),^[2] while less experienced hunters can be just as capable with the .243 because of its very low recoil yet high velocity.^[7][11][13] Besides hunting applications, the cartridge is popular with target and metallic silhouette shooters for those same recoil and velocity properties, with superb accuracy.^[12]

The .243 Winchester has regularly made the top five of rankings for "Best Whitetail Deer Hunting Cartridges" from sources such as Field and Stream^[14] and Outdoor Life,^[2][15] and its widespread popularity (called the "whitetail hunter's favorite" by the Browning Arms Company^[16] and "American favorite" by American Rifleman^[7]) assures chamberings in newly manufactured offerings of not only bolt-action rifles, but also semiautomatic rifles (e.g., Browning BAR and AR-10 platforms), lever action rifles (e.g., Henry Long Ranger and Browning BLR), and even pump action rifles (e.g., Remington 7600).^[2] Gun Digest estimates that (as of the end of 2018) the .243 Winchester is the second-most popular of all hunting rifle chamberings (after the long action .30-06).^[17]