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.223 Remington

Introduced 1964Remington ArmsCIP standard

Also known as 223 Rem., 5.56x45mm — the same cartridge under different names, all of which find this page.

Dimensions and pressure

Generated from the schema, like every specification table on this site, so a figure recorded on this entry cannot be missing from the table.

Identity
Designed by
Remington Arms
Introduced
1964
Production
not recorded
Standards body
C.I.P.
Case type
Rimless
Case shape
Bottleneck
Dimensions
Bullet diameter
5.7 mm0.2244 insource

Cartridge maximum, dimension G1.

Bore diameter
not recorded
Case length
44.7 mm1.760 insource

Cartridge maximum, dimension L3.

Overall length
57.4 mm2.260 insource

Cartridge maximum, dimension L6.

Rim diameter
9.6 mm0.3780 insource

Dimension R1.

Neck diameter
6.43 mm0.2531 insource

Dimension H2.

Base diameter
9.58 mm0.3772 insource

Dimension P1.

Pressure
Maximum pressure
430 MPa62,366 psisource

Pmax 4300 bar, transducer method.

Pressure standard
C.I.P.

SAAMI and C.I.P. measure pressure differently and their figures are not interchangeable, which is why the body is always named beside the figure.

Loads

Velocity is recorded per barrel length as published. A gun page interpolates between these points and never projects beyond them.

American Eagle 55 gr FMJ

Federal

Bullet mass
3.564 g55.00 grsource

55 gr as published, converted to grams.

Cartridge mass
not recorded
Bullet type
FMJ boat tail
G1 BC
0.269source

G1 ballistic coefficient as published.

G7 BC
not recorded

Chambered in

Computed from every entry that lists this cartridge. Nothing here is hand-maintained.

Gallery

A .223 Remington cartridge photographed beside a 5.56x45mm NATO cartridge for comparison

Image credit

Title
Caliber cartridge comparison - .223 Remington and 5.56x45mm NATO
Author
Grasyl(attribution required)
Licence
CC BY-SA 4.0
Source
https://commons.wikimedia.org/wiki/File:Caliber_cartridge_comparison_-_.223_Remington_and_5.56x45mm_NATO.jpg
The .223 Remington beside the 5.56x45mm NATO round it shares a case with.

Detail

Remington released this in 1964 as the commercial form of the experimental round developed for the ArmaLite AR-15 trials. It is the civil twin of the 5.56x45mm NATO cartridge and the pair are not symmetric: a rifle chambered for the NATO round will fire either, while a rifle chambered and proof-tested to the commercial specification should be fed only the commercial round. The difference is in the throat ahead of the case mouth rather than in the ammunition.

The two standards bodies do not agree on the pressure either, and not because they disagree about the cartridge. C.I.P. records 430 MPa and SAAMI records 55,000 psi, which is about 379 MPa; the figures are taken at different points by different methods and cannot be compared as though they were the same measurement. The C.I.P. number is the one recorded here, and the field beside it names the body.

No velocity is listed. Federal publishes 3,240 feet per second for this load and does not publish the barrel length it was measured in, and a velocity without a barrel length is not a fact about anything.

References

  1. C.I.P. TDCC datasheet, 223 Rem. · Tab. I, dated 1984-06-14, revision 2017-05-17 · read 2026-08-27
  2. American Eagle Rifle .223 Rem 55 grain FMJ (AE223) · read 2026-08-27

Last verified 2026-08-27 · review status: spot-checked