History
The .223 Remington came out of the U.S. military's late-1950s search for a small-caliber, high-velocity rifle round. ArmaLite's Eugene Stoner scaled down his AR-10, and the work started from the .222 Remington, a 1950 varmint cartridge.1
The .222 could not quite meet the Army's velocity and penetration requirements, so Remington enlarged the case into the .222 Remington Special in 1959, which was soon renamed the .223 Remington. The military recommended the AR-15 in .223 in July 1962, standardized the round as the 5.56x45mm M193 in 1963, and adopted the M16 in 1964. Remington offered the first commercial rifle in the chambering, the Model 760, in late 1963.1
Lineage
The .223 Remington descends from the .222 Remington family by way of the .222 Remington Special.1 It fires a .224 inch bullet. Its higher-pressure military sibling is the 5.56x45mm NATO, which shares the case but runs hotter through a longer throat, and the .300 Blackout is built from shortened, resized .223 brass.
Specifications
| Spec | Value |
|---|---|
| Case type | Rimless, bottlenecked |
| Bullet diameter | 5.69 mm (.224 in) |
| Neck diameter | 6.43 mm (.2530 in) |
| Base diameter | 9.58 mm (.3770 in) |
| Rim diameter | 9.60 mm (.3780 in) |
| Case length | 44.70 mm (1.760 in) |
| Overall length | 57.40 mm (2.260 in) |
| Case capacity | ~28 to 31 gr H2O (varies by brand) |
| Primer size | Small rifle |
| Belted | No |
| Rifling twist | 1 in 12 in (305 mm, C.I.P. reference)2 |
| Max pressure | 55,000 psi (SAAMI); 4,300 bar / 430 MPa (C.I.P.)2 |
| Recommended barrel | 26 in, 1:8 twist (heavy match bullets) |
Barrel Design
The .223 splits into two worlds, and twist is the divider. The old C.I.P. reference twist of one turn in 12 inches stabilizes light 55 grain bullets and nothing heavier. To shoot the long 70 to 80 grain match bullets that make the .223 worth ranging out past 600 yards, you need a 1:8 twist, with 1:7 giving margin for the heaviest.
Length follows the bullet. A precision .223 build favors 20 to 26 inches so the powder burns fully behind a heavy bullet, while a 16 inch carbine gives up real velocity. A shorter 20 to 24 inch barrel handles quickly and suits a positional or carbine setup, but the recommendation here is a 26 inch, 1:8 barrel. The extra length holds velocity on the heavy 73 to 77 grain match bullets and tightens the velocity spread a handloader works to control, and the tables below are computed there.
Range Ammo Performance
Federal American Eagle · 55 gr 55 gr FMJ-BT $0.52/rd
| Range (yd) | Velocity (fps) | Elevation (mil) | Energy (ft-lb) | Windage (mil) |
|---|---|---|---|---|
| 0 | 3290 | -0.3 | 1322 | 0.6 |
| 100 | 2938 | 0.0 | 1054 | 0.3 |
| 200 | 2612 | -0.3 | 833 | 0.6 |
| 300 | 2308 | -0.9 | 651 | 1.0 |
| 400 | 2025 | -1.6 | 501 | 1.4 |
| 500 | 1765 | -2.6 | 380 | 1.8 |
| 600 | 1531 | -3.7 | 286 | 2.3 |
| 700 | 1331 | -5.2 | 216 | 2.9 |
| 800 | 1174 | -6.9 | 168 | 3.6 |
| 900 | 1065 | -9.1 | 139 | 4.3 |
| 1000 | 989 | -11.7 | 120 | 5.0 |
| 1100 | 931 | -14.7 | 106 | 5.7 |
Muzzle velocity 3290 fps is estimated at 26 in from the 24 in factory figure of 3240 fps at about 25 fps per inch. Expect your own barrel to read a little differently. Velocity is color coded green supersonic, yellow transonic, red subsonic; treat transonic and subsonic rows as approximate.
Match Ammo Performance
Hornady ELD Match · 73 gr 73 gr ELD Match $1.15/rd
| Range (yd) | Velocity (fps) | Elevation (mil) | Energy (ft-lb) | Windage (mil) |
|---|---|---|---|---|
| 0 | 2840 | -0.4 | 1307 | 0.5 |
| 100 | 2622 | 0.0 | 1114 | 0.2 |
| 200 | 2414 | -0.4 | 944 | 0.5 |
| 300 | 2215 | -1.2 | 795 | 0.8 |
| 400 | 2026 | -2.0 | 665 | 1.0 |
| 500 | 1846 | -3.0 | 552 | 1.4 |
| 600 | 1674 | -4.2 | 454 | 1.7 |
| 700 | 1509 | -5.5 | 369 | 2.1 |
| 800 | 1351 | -7.0 | 296 | 2.6 |
| 900 | 1204 | -8.8 | 235 | 3.1 |
| 1000 | 1088 | -10.9 | 192 | 3.6 |
| 1100 | 1035 | -13.4 | 173 | 4.2 |
Muzzle velocity 2840 fps is estimated at 26 in from the 24 in factory figure of 2790 fps at about 25 fps per inch. Expect your own barrel to read a little differently. Velocity is color coded green supersonic, yellow transonic, red subsonic; treat transonic and subsonic rows as approximate.
Trajectory
FAQ
Can I shoot 5.56 NATO in a .223 Remington rifle?
Not safely in a true .223 chamber. A 5.56 cartridge fired in a .223 chamber can spike pressure roughly 10,000 psi over the .223's working level because of the shorter throat.3 Firing .223 in a 5.56 chamber is fine.
What is the actual pressure difference between .223 and 5.56?
The 5.56 NATO runs to about 58,000 psi against the .223's roughly 55,000 psi, and the 5.56 chamber adds about an eighth inch of throat that lets it run a bit more powder.3
What twist do I need for heavy .223 match bullets?
At least a 1:8 for the 73 to 77 grain class, and a 1:7 for 80 grain and up. The legacy 1:12 only stabilizes light 55 grain bullets.2
What barrel length suits precision .223?
Twenty to 26 inches. The longer barrel lets slow powders push heavy, high-BC bullets to full velocity; a 16 inch carbine trades meaningful speed for handiness.
Citations
- (2019). How .223 Remington Came To Be. NRA Shooting Sports USA. accessed 2026-05-30.
- (2017). C.I.P. TDCC Datasheet — .223 Remington. Commission Internationale Permanente (C.I.P.). accessed 2026-05-30.
- (2024). What is the difference between 5.56 NATO and 223 Rem. Hornady Law Enforcement. accessed 2026-05-30.