.223 Remington

.223 Remington
A variety of .223 Remington cartridges with a .308 Winchester (right) for comparison
Type	Rifle
Place of origin	United States
Production history
Designer	Remington Arms
Designed	1962
Produced	1964–present
Variants	5.56×45mm NATO
Specifications
Parent case	.222 Remington
Case type	Rimless, bottleneck
Bullet diameter	0.224 in (5.7 mm)
Neck diameter	0.253 in (6.4 mm)
Shoulder diameter	0.354 in (9.0 mm)
Base diameter	0.376 in (9.6 mm)
Rim diameter	0.378 in (9.6 mm)
Rim thickness	0.045 in (1.1 mm)
Case length	1.76 in (45 mm)
Overall length	2.26 in (57 mm)
Case capacity	28.8 grain H2O (1.87 ml)
Rifling twist	1 in 12 in (305 mm) (military-style rifles use 1 in 7 in (178 mm) to 1 in 10 in (254 mm) to stabilize longer bullets)
Primer type	Small rifle
Maximum pressure (SAAMI)	55,000 psi (380 MPa)
Maximum pressure (CIP)	62,366 psi (430.00 MPa)
Maximum CUP	52000 CUP
Ballistic performance
Bullet mass/type Velocity Energy 36 gr (2 g) JHP 3,750 ft/s (1,140 m/s) 959 ft⋅lbf (1,300 J) 55 gr (4 g) Nosler ballistic tip 3,240 ft/s (990 m/s) 1,265 ft⋅lbf (1,715 J) 60 gr (4 g) Nosler partition 3,160 ft/s (960 m/s) 1,325 ft⋅lbf (1,796 J) 69 gr (4 g) BTHP 2,950 ft/s (900 m/s) 1,338 ft⋅lbf (1,814 J) 77 gr (5 g) BTHP 2,750 ft/s (840 m/s) 1,301 ft⋅lbf (1,764 J)
Test barrel length: 24 inches (61 cm) Source(s): [1][2]

The .223 Remington (designated 223 Remington by SAAMI^[4] and 223 Rem. by the C.I.P.^[5]) is a rimless, bottlenecked, centerfire intermediate cartridge. It was developed in 1957 by Remington Arms and Fairchild Industries for the U.S. Continental Army Command of the United States Army as part of a project to create a small-caliber, high-velocity firearm. The .223 Remington is considered one of the most popular common-use cartridges and is currently used by a wide range of semi-automatic and manual-action rifles.