.223 Remington

The .223 Remington (designated 223 Remington by SAAMI^[3] and 223 Rem. by the C.I.P.^[4]) 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 used by a wide range of semi-automatic and manual-action rifles.

.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]

History

From left: .222 Remington, .223 Remington, and 5.56×45mm NATO

The development of the cartridge, which eventually became the .223 Remington, was linked to the development of a new lightweight combat rifle. The cartridge and rifle were developed by Fairchild Industries, Remington Arms, and several engineers working toward a goal developed by U.S. Continental Army Command (CONARC). Development began in 1957. A project to create a small-caliber, high-velocity (SCHV) firearm was created. Eugene Stoner of ArmaLite was also invited to scale down the AR-10 (7.62×51mm NATO) design.^[5] Winchester was also invited to participate.^[6][7]

CONARC ordered rifles to test. Stoner and Sierra Bullet's Frank Snow began work on the .222 Remington cartridge. Using a ballistic calculator, they determined that a 55-grain bullet would have to be fired at 3,300 ft/s to achieve the 500-yard performance necessary.^[7]

Robert Hutton (technical editor of Guns and Ammo magazine) started the development of a powder load to reach the 3,300 ft/s goal. He used DuPont IMR4198, IMR3031, and an Olin powder to work up loads. Testing was done with a Remington 722 rifle with a 22" Apex barrel. During a public demonstration, the round successfully penetrated the US steel helmet as required, but testing also showed chamber pressures to be too high.^[6][7]

Stoner contacted both Winchester and Remington about increasing the case capacity. Remington created a larger cartridge called the .222 Special. This cartridge is loaded with DuPont IMR4475 powder.^[7]

During parallel testing of the T44E4 (future M14) and the ArmaLite AR-15 in 1958, the T44E4 experienced 16 failures per 1,000 rounds fired compared to 6.1 for the ArmaLite AR-15.^[7] Because of several different .222 caliber cartridges that were being developed for the SCHV project, the .222 Special was renamed .223 Remington. In May 1959, a report was produced stating that five- to seven-man squads armed with ArmaLite AR-15 rifles have a higher hit probability than 11-man squads armed with the M-14 rifle. At an Independence Day picnic, Air Force General Curtis Le May tested the ArmaLite AR-15 and was very impressed with it. He ordered a number of them to replace M2 carbines that were in use by the Air Force. In November of that year, testing at Aberdeen Proving Ground showed the ArmaLite AR-15 failure rate had declined to 2.5/1,000, resulting in the ArmaLite AR-15 being approved for more extensive trials.^[7]

In 1961, marksmanship testing compared the AR-15 and M-14; 43% of ArmaLite AR-15 shooters achieved Expert, while only 22% of M-14 rifle shooters did. Le May ordered 80,000 rifles.^[7] In July 1962, operational testing ended with a recommendation for the adoption of the ArmaLite AR-15 rifle chambered in .223 Remington.^[7] In September 1963, the .223 Remington cartridge was officially accepted and named "Cartridge, 5.56 mm ball, M193". The following year, the ArmaLite AR-15 was adopted by the United States Army as the M16 rifle, and it would later become the standard U.S. military rifle. The specification included a Remington-designed bullet and the use of IMR4475 powder, which resulted in a muzzle velocity of 3,250 ft/s and a chamber pressure of 52,000 psi.^[7]

In the spring of 1962, Remington submitted the specifications of the .223 Remington to the Sporting Arms and Ammunition Manufacturers' Institute (SAAMI). In December 1963, Remington introduced its first rifle chambered for .223 Remington a Model 760 rifle.^[6]

Cartridge dimensions

The .223 Remington has a 1.87 mL (28.8 gr H₂O) cartridge case capacity.^[8]

.223 Remington maximum CIP cartridge dimensions. All sizes in millimeters (mm).^[9]

Americans would define the shoulder angle at alpha/2 = 23 degrees. The common rifling twist rate for this cartridge is 305 mm (1 in 12 in), 6 grooves, Ø lands = 5.56 millimetres (0.219 in), Ø grooves = 5.69 millimetres (0.224 in), land width = 1.88 millimetres (0.074 in) and the primer type is small rifle.

According to the official CIP rulings, the .223 Remington can handle up to 430.00 MPa (62,366 psi) P_max piezo pressure. In CIP-regulated countries, every rifle cartridge combination has to be proofed at 125% of this maximum CIP pressure to certify for sale to consumers.^[9] This means that .223 Remington chambered arms in CIP-regulated countries are as of 2016^[update] proof tested at 537.50 MPa (77,958 psi) PE piezo pressure. This is equal to the NATO maximum service pressure guideline for the 5.56×45mm NATO cartridge.

The SAAMI pressure limit for the .223 Remington is set at 379.212 MPa (55,000 psi), piezo pressure.^[10][11] Remington submitted .223 Remington specifications to SAAMI in 1964.^[7]

.223 Remington vs. 5.56×45mm NATO

In 1980, the .223 Remington was transformed into a new cartridge and designated 5.56×45mm NATO (SS109 or M855).^[7]

Dimensions

The external dimensional specifications of .223 Remington and 5.56×45mm NATO brass cases are nearly identical. The cases tend to have similar case capacity when measured (case capacities have been observed to vary by as much as 2.6 grains (0.17 ml)), although the shoulder profile and neck length are not the same and 5.56×45mm NATO cartridge cases tend be slightly thicker to accommodate higher chamber pressures. When hand-loaded, care is taken to look for pressure signs as 5.56×45mm NATO cases may produce higher pressures with the same type of powder and bullet as compared to .223 Remington cases. Sierra provides separate loading sections for .223 Remington and 5.56×45mm NATO and also recommends different loads for bolt-action rifles as compared to semiautomatic rifles.^[8][12]

Pressures

Remington submitted the specifications for the .223 Remington cartridge in 1964 to SAAMI. The original pressure for the .223 Remington was 52,000 psi with DuPont IMR Powder. A higher pressure of 55,000 psi (379 MPa) resulted from the change from IMR to Olin Ball powder.^[7] The official name for .223 Remington in the US Army is cartridge 5.56x45mm ball, M193. If a 5.56×45mm NATO cartridge is loaded into a chamber intended to use .223 Remington, the bullet will be in contact with the rifling and the forcing cone is very tight. This generates a much higher pressure than .223 Remington chambers are designed for.^[8] NATO chose a 178-mm (1-in-7) rifling twist rate for the 5.56×45mm NATO chambering. The SS109/M855 5.56×45mm NATO ball cartridge requires a 228 mm (1-in-9) twist rate, while adequately stabilizing the longer NATO L110/M856 5.56×45mm NATO tracer projectile requires an even faster 178 mm (1-in-7) twist rate.^[7]

Chambers

The .223 Remington and 5.56×45mm NATO barrel chamberings are not the same.^[13] While the cartridges are identical other than powder load, bullet weight, and chamber pressure, a significant difference is in the barrel of the rifle to be used, not in the cartridge. The 5.56×45mm NATO chambers are dimensionally larger in certain critical areas than .223 Remington chambers. As the chambers differ accordingly the head space gauges used for the two chamberings differ.^[14]

By observation, 5.56×45mm NATO ammunition is not as accurate as .223 Remington in many of the AR-type rifles extant, even with the same bullet weight. The .223 Wylde chamber specification developed by Bill Wylde solves this problem by using the external dimensions and lead angle as found in the military 5.56×45mm NATO cartridge and the 0.224 inch freebore diameter as found in the civilian SAAMI .223 Remington cartridge. It was designed to increase the accuracy of 5.56×45mm NATO ammunition to that of .223 Remington.^[15] Other companies also have chamber designs that increase 5.56×45mm NATO accuracy.^[16]

Comparisons

The table contains some estimated pressures based on normal proofing practice and on the known increases in pressure caused by bullet setback (which is a similar occurrence with regard to pressure). The proof pressure of M197 is 70,000 psi.^[17]

The following table shows the differences in nomenclature, rifling, throating, and normal, maximum, and safe pressures:^[7][6]

Cartridge	US designation	NATO designation	Bullet	Rifling	Throat	Pressure in NATO chamber	in 223 SAAMI chamber	Safe sustained
223 Remington	223 Rem		55 gr FMJ	1:14	tight	52,000 psi (359 MPa)	52,000 psi (359 MPa)	Yes
223 Remington	M193	5.56×45mm	55 gr FMJ	1:12	tight	55,000 psi (379 MPa)	55,000 psi (379 MPa)	Yes
223 Remington	M196	5.56×45mm	54 gr Tracer	1:12	tight	55,000 psi (379 MPa)	55,000 psi (379 MPa)	Yes
223 Remington	M197		C10524197-56-2	1:12	tight	70,000 psi (483 MPa)	70,000 psi (483 MPa)	One time only
5.56×45 mm NATO	M855	SS109	62 gr ball	1:7	long	62,366 psi (430 MPa) EPVAT	over 70,000 psi (483 MPa)	No
5.56×45 mm NATO	M856	L110	77 gr Tracer	1:7	long	62,366 psi (430 MPa) EPVAT	over 70,000 psi (483 MPa)	No
5.56×45 mm NATO	M857	SS111	Tungsten carbide	1:7	long	62,366 psi (430 MPa) EPVAT	over 70,000 psi (483 MPa)	No
5.56×45 mm NATO	Proof	Proof	unknown	1:7	long	77,958 psi (538 MPa) EPVAT	82,250 psi (567 MPa) estimated	No

Beside the NATO EPVAT testing pressure testing protocols the other employed peak pressure measurement methodology or methodologies to correlate this table remain unknown.

Effects of barrel length on velocity

Barrel length helps determine a specific cartridge's muzzle velocity. A longer barrel typically yields a greater muzzle velocity, while a shorter barrel yields a lower one. The first AR-15 rifles used a barrel length of 20". In the case of the 223 Remington (M193), ammunition loses or gains about 25.7 ft/sec (7.8 m/s) for each inch of barrel length, while 5.56×45 mm NATO (M855) loses or gains 30.3 ft/sec (9.2 m/s) per inch of barrel length.^[18]

Usage and commercial offerings

(Left to right) .223 Rem, .243 Win, .308 Win

The .223 Remington has become one of the most popular cartridges and is currently used in a wide range of semiautomatic and manual-action rifles and even handguns, such as the Colt AR-15, Ruger Mini-14, Remington Model 700.^[19][20] The popularity of .223 Remington is so great, that in the US it virtually eliminated all other similar .22 caliber center-fire varmint rifle cartridges.^[21][22]

It is commercially loaded with 0.224-inch (5.7 mm) diameter jacketed bullets, with weights ranging from 35 to 85 grains (2.27 to 5.8 g), with the most common loading by far being 55 gr (3.6 g). Ninety-grain and 95-grain (6.2 g) Sierra Matchking bullets are available for reloaders.^[23]

See also

• .30 RAR
• 5 mm caliber
• 6×45mm
• Delta L problem
• List of rifle cartridges
• Sectional density
• Table of handgun and rifle cartridges

References

1. "223 REM". federalpremium.com. Archived from the original on 2017-03-06. Retrieved 9 March 2017.
2. "223 Remington". black-hills.com. Archived from the original on May 31, 2023. Retrieved 9 March 2017.
3. "Voluntary Industry Performance Standards for Pressure and Velocity of Centerfire Rifle Ammunition for the Use of Commercial Manufacturers" (PDF). Sporting Arms and Ammunition Manufacturers' Institute. Retrieved 19 December 2023.
4. "223 Rem" (PDF). Commission internationale permanente pour l'épreuve des armes à feu portatives. Retrieved 19 December 2023.
5. "History of the .223 Remington Cartridge". Fenix Ammunition. Archived from the original on May 6, 2023. Retrieved 2021-04-25.
6. Barnes, Frank C. (2016). Cartridges of the World. Iola, WI, US: Krause Publishing. p. 88. ISBN 978-1-4402-4265-6.
7. Watters, Daniel. "A 5.56 X 45mm 'Timeline'". thegunzone.com. Archived from the original on 9 February 2004. Retrieved 6 March 2017.
8. "223 Rem + 223 AI Cartridge Guide". 6mmbr.com. Archived from the original on March 21, 2023. Retrieved 8 March 2017.
9. "C.I.P. TDCC .223 Rem" (PDF). CIP. Archived from the original (PDF) on 2018-06-21. Retrieved 2018-06-21.
10. "SAAMI Pressures". Leverguns.com. Archived from the original on 14 October 2007. Retrieved 2007-11-29.
11. "ANSI/SAAMI Velocity & Pressure Data: Centerfire Rifle" (PDF). Saami.org. Archived from the original (PDF) on 2013-07-02. Retrieved 2007-11-29.
12. "5.56 vs .223 – What You Know May Be Wrong". LuckyGunner.com. June 22, 2012. Archived from the original on May 29, 2023. Retrieved June 13, 2013.
13. ".223 Remington and 5.56×45mm NATO Chamber dimensions differences". imageshack.us. Archived from the original on March 15, 2014.
14. NATO Chamber Headspace GagesAvailable for 5.56 NATO and 7.62 NATO
15. "Clearing the Caliber Confusion: .223 Wylde vs. 5.56 NATO". American Weapons Components. 16 September 2016. Archived from the original on December 18, 2022.
16. "Noveske Rifleworks 13.7" 5.56 Infidel Gen III Complete Upper". Primaryarms.com. Archived from the original on December 18, 2022. Retrieved 8 March 2017.
17. Barnes, Frank C. (2014). Cartridges of the World. Iola, WI, US: Krause Publishing. p. 688. ISBN 978-1-4402-4265-6.
18. "223 Remington/5.56 NATO, velocity versus barrel length: A man, his chop box and his friend's rifle". Rifleshooter.com. 20 April 2014. Archived from the original on December 30, 2022.
19. ".223 Rem". Archived from the original on April 4, 2023.
20. "What are the most popular calibers in the US?". 14 September 2015. Archived from the original on July 15, 2023.
21. "223 vs. 308 - A Rifle Caliber Comparison". 15 August 2018. Archived from the original on January 19, 2019.
22. "Compared: Varmint Cartridges (.204 Ruger, .223 Rem., .22-250 Rem., .243 Win. And .25-06 Rem.)". Archived from the original on June 28, 2023.
23. ".22 Caliber (.224) 90 gr. HPBT MatchKing". Sierra Bullets. Archived from the original on 2015-04-27.

External links

• .223 Remington Cartridge Guide by AccurateShooter.com
• A 5.56×45mm Timeline by Daniel Watters
• Ballistics By The Inch .223 Remington results.