Ammunition: the .223 Remington caliber

A series of introductory articles conceived to teach beginners specs, features and history of the most popular rifle ammunition calibers

The .223 Remington cartridge was born halfway through the 1960s; it can be considered as a "civilian version" of the 5,56x45mm M193 Ball cartridge, adopted by the U.S. Armed Forces for the new M16 service rifle, which replaced the M14 7,62x51mm caliber battle rifle; with the M16/5,56mm rifle-caliber combo, the U.S. forces abandoned the old .30 caliber issue and embraced outright the philosophy of intermediate or light-caliber service rifles.

Some history

The work of American engineers in the creation of the .223 Remington round didn't stand out for originality, since the caliber is, more or less, an extremely size-reduced version of the old .30-06 Springfield cartridge.

An U.S. Army Sergeant uses his M16 service rifle against advancing Viet-Congs in Loc Minh, Vietnam (October 1967)

After the U.S. military adoption of the .223 Remington/5,56x45mm caliber, most NATO and other allied Countries quickly followed the American lead − which led to a boom in popularity and diffusion of said caliber worldwide.

More specifically speaking, the .223 cartridge spawns from a modified .222 Remington sporting round, modified with a longer case and a shorter neck to enhance its propellant capacity and thus the round's performance, allowing the use of .22 caliber balls ranging between 50 grains and 69 grains in weight − as long as the gun in use features the right barrel rifling pitch, that is.

Ammunition: the .223 Remington caliber
The .223 Remington round in a classic 55-grains FMJ load

The military history of the .223/5,56mm cartridge is tied to the above-mentioned M16 rifle and to all its variants, as well as to a plethora of similar platforms. As of today, most modern sporting rifles are still chambered in 5,56mm/.223 Remington, and enjoy a high degree of popularity between hunters and sport shooters alike all over the world.

The cartridge

As its own name states, the Remington Arms Company was the world's first maker to fully understand the practical versatility and the potential for commercial success of the .223 Remington round, and to manufacture it for civilian sales just shortly before its first official U.S. adoption; the wide availability of military surplus, just a couple of years later, would also have made more practical to acquire and reload in high quantities. 

Ammunition: the .223 Remington caliber
A GECO .223 Remington load with 63-grains FMJ balls, specifically conceived for sport shooting and semiautomatic firearms
Ammunition: the .223 Remington caliber
A Barnes VOR-TX .223 Remington 55-grains "Triple-Shock X" varmint load

Shortly thereafter, most − if not all − the most important ammunition manufacturers started to offer a plethora of .223 Remington/5,56mm loads, as gunmakers ramped up their production of civilian-grade and military firearms in said caliber.
Today, basically every type of firearm is available in a .223 Remington caliber, from large-size handguns all the way down to Express rifles − with semiautomatic and bolt-action rifles and carbines still making up the bulk of the global production of .223-caliber platforms for civilian and professional uses.

Ammunition: the .223 Remington caliber
The Winchester .223 Remington "Supreme" hunting rounds are loaded with 55-grains Ballistic Silvertip balls
Ammunition: the .223 Remington caliber
The Norma Match .223 Remington round, loaded with 77-grains Sierra Match King HPBT ball, was conceived for long-range shooting with rifles offering a 1:7 or 1:8 barrel rifling twist

The .223 Remington round is extremely pleasurable to shoot, with a recoil level close to zero; it is very accurate up to 200 metres of distance and even beyond, and it's cheap to purchase and even cheaper (and extremely easy indeed) to hand-reload. The standard load for the .223 Remington round provide for the use of a 55 grains ball traveling at an extremely high velocity level − around 950 metres-per-second − which is also one of the causes of its many limits as a small caliber round.

Unlike higher-caliber rounds, .223 Remington is particularly sensitive to wind − most notably side wind − which can affect its accuracy on long range shots. It can also lack the necessary knockdown power to be used effectively on big game, due to its combination of small size and high muzzle velocity, may cause it to disintegrate immediately upon impact with large preys, causing only superficial wounds.  

Haenel CR-223
Haenel CR-223 semiautomatic rifle offers a plethora of factory-issued features such as a collapsing stock, a set of folding iron sights, and a monolithic upper receiver
SIG Sauer P556 Classic Pistol
Some Countries allow the civilian ownership and use of .223-caliber, "military-style" semiautomatic centerfire handguns, such as the SIG Sauer P556 Classic Pistol model

Fields of use

Remington Varmint SPS TAC
A Remington Varmint SPS TAC .223 caliber bolt-action rifle, sporting a 510mm-long barrel
Ruger 77 VT SS 
A Ruger 77 VT SS .223 Remington caliber, laminated wooden stock bolt-action hunting rifle

Due to its intrinsic limitations, the usefulness of the .223 Remington round in hunting is somewhat limited; it still has its niche of enthusiast users, particularly in small game and varmint hunt. Its accuracy allows shooters to engage small preys even at its maximum ranges. This kind of use is mostly popular in the United States, much less in Europe where it can be severely restricted by national hunting laws or local hunt regulations. It's the author's personal opinion that the .223 Remington/5,56x45mm round should not be used on deer, boars, and ungulates in general, as its terminal ballistics may not guarantee clean kills on large venison.

In basically all Countries where civilian ownership of semiautomatic centerfire rifles, the main use for the .223 Remington round is sport shooting. Hereby portrayed, an FNH-USA FN15 semiautomatic carbine
M4-type semiautomatic carbine
In basically all Countries where civilian ownership of semiautomatic centerfire rifles, the main use for the .223 Remington round is sport shooting. Hereby portrayed, an M4-type semiautomatic carbine with MagPul P-MAG magazine and MOE pistol grip, handguard, foregrip, stock and folding rear sight

From a purely civilian standpoint, the 5,56x45mm/.223 Remington round gives its best at the range; the firearms industry is well aware of this, and offers a plethora of different rifles and carbines in this caliber − of any mode of operation, barrel lenght, design, stock lenght, barrel rifling pitch and more. Just like .308 Winchester, the .223 Remington cartridge has established itself as a popular round for civilian long-range sport shooting specialties, and its popularity is resisting very well to the current growing wave of the intermediate cartridges launched in the past years to "supersede" it. The .223 Remington/5,56mm round allows to spend very long, very funny days at the range with no recoil stress whatsoever for the shooter. Although less accurate than the earier .222 Remington, the .223 Remington/5,56x45mm round is extremely accurate for sport shooting in its most common factory loads, and with the right hand-reload can become outright excellent.


Civilian-grade firearms chambered in .223 Remington can handle military surplus 5,56x45mm rounds, but military loads often reach higher pressure levels, so the structural strenght and the wear of the gun should be taken in consideration.

Just like with .308 Winchester/7,62x51mm, the military-standard brass for the 5,56x45mm is generally harder and thicker than the civilian-grade .223 Remington brass; hand-reloading enthusiasts should take in consideration the idea of decreasing the propellant load of around 10% from the standards, when reloading military-grade brass. Higher doses could be experimented later, step by step, with smaller additions of propellant.

Despite being very similar to the .222 Remington Magnum cartridge, the 5,56x45mm/.223 Remington round is absolutely NOT compatible with it.

The small .223 caliber ball is extremely sensitive to the rifling pitch of the barrel it's fired through; using high-weight load on barrels with inadequate rifling pitch could cause a "Keyholing" effect − that meaning, the bullet may loose stability in mid-flight and hit the target sideways.

Also known as: 

5,6x45 – 5,56x45mm NATO – 5,56 Nato – 5,56 OTAN

Some examples of reloading specs for the .223 Remington cartridge

Gun: Remington Police LTR 
 Barrel lenght: 510 mm (heavy profile)






.223 Remington 

Vihtavuori N140

24,5 grains

Sierra BT 55

CCI S.R. Standard

.223 Remington

IMR 4198

21 grains

Speer BT 50  

CCI S.R. Standard

.223 Remington 

Winchester 748 

24 grains

Sierra BT 60

CCI S.R. Standard 


Our readers should be advised that ammunition handloading requires skill and attention. All provided handloading data should be considered as purely indicatory; even the slightest variations could cause dangerous pressure surges, which could in turn result into bodily harm or property damage. In no case will the author of this article or accept any responsibility for any injury or damage caused by the improper use of these data.

Ammunition: the .223 Remington caliber
Semiautomatic rifle Thor CQB TR15, .223 caliber
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