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Regardless of the plentiful similarities and an identical exterior case dimensions of the .223 Remington and 5.56x45mm NATO cartridges, a deep dive into the 2 exposes some minor, but essential variations. Since their inception, these two cartridges have change into among the hottest centerfire cartridges of all-time with widespread purposes. 

Even with the recognition of those two cartridges, there are nonetheless many widespread misunderstandings and questions on their variations. Primarily, is 5.56 NATO and .223 Remington ammunition interchangeable? The reply is each sure and no. Put most easily, .223 Rem. ammunition can safely be fired out of rifles chambered in 5.56 NATO, however the identical can’t be mentioned when firing 5.56 NATO ammunition in a .223 chamber. 

A sampling of the 5.56 ammo we examined. Tyler Freel

No less than that’s what we’re informed. Because of the improve in chamber strain when firing 5.56 NATO ammunition, paired with the marginally shorter throat in .223 chambered rifles, shooters are warned that 5.56 NATO ammunition shouldn’t be fired in rifles chambered in .223 Rem. The 2 share practically an identical case dimensions and hearth the identical bullets, permitting shooters to simply chamber ammunition with each cartridges however simply because you’ll be able to doesn’t imply you must. Right here’s what you want to know concerning the 5.56 vs .223.

.223 Remington Specs

Bullet Diameter: 0.224 inches
Case Size: 1.76 inches
General Size: 2.26 inches
Dad or mum Case: .222 Remington
Case Capability: 28.8 grains H2O
SAAMI Chamber Strain: 55,000 psi

5.56x45mm NATO Specs

Bullet Diameter: 0.224  inches
Case Size: 1.76 inches
General Size: 2.26 inches
Dad or mum Case: .223 Remington
Case Capability: 28.5 grains H2O
SAAMI Chamber Strain: 61,000 psi

Historical past

Remington Arms formally submitted the .223 Remington cartridge design to SAAMI in 1962 after a number of years of analysis and improvement together with the U.S. Continental Military Command, Fairchild Industries, and Eugene Stoner of Armalite. The work with Stoner was vital as a consequence of his major position within the invention and implementation of the AR-10 platform. Their shared aim was to create a light-weight cartridge and rifle mixture that supplied acceptable terminal ballistics at prolonged distances on a extra nimble platform in comparison with the AR-10 chambered in 7.62x51mm NATO. 

The top end result was the launch of Armalite’s AR-15 rifle, chambered in .223 Remington, propelling a 55-grain bullet at 3,250 fps. Two years after its submission to SAAMI, the U.S.  Military adopted Armalite’s AR-15 rifle, dubbed the M16. The M16 first noticed fight within the Vietnam warfare and went on to change into the usual navy issued service rifle in 1969. Since then, the .223 Remington cartridge has expanded to just about each taking pictures endeavor from searching to aggressive taking pictures and every thing in between. The success of the .223 Remington additionally expands past its AR-15 roots and it’s generally chambered in all kinds of rifle configurations.

Following the success of the .223 Rem., NATO signed an settlement in 1977 to start the choice strategy of changing the 7.62x51mm NATO cartridge. FN Herstal answered the decision, creating the 5.56 NATO cartridge, which solely barely differentiated itself from the .223 Rem. That distinction between the 2 cartridges got here within the type of thicker walled brass which created a barely smaller case capability for the 5.56 NATO cartridge. The marginally thicker partitions and smaller case capability allowed the 5.56 NATO to deal with the rise in strain from heavier cost weights, therefore the favored warning that 5.56 NATO ammunition shouldn’t be fired in rifles chambered in .223 Rem.

For comparability, the 5.56 NATO has a most of 61,000 PSI of chamber strain whereas the SAAMI authorised chamber strain for the .223 Rem. is 55,000 PSI.

By late 1980, NATO formally adopted and standardized the 5.56 NATO cartridge. Quick ahead 40 years and the 5.56 NATO continues to be considered one of, if not probably the most, used cartridge amongst navy forces worldwide. That reality alone speaks volumes to the validity and effectiveness of the cartridge.

The .223 Wylde

Plenty of 5.56 NATO ammunition is commercially obtainable, and as a common answer to the discrepancy between 5.56 and .223 chambers, a number of rifle producers started chambering rifles in .223 Wylde, which was developed by Invoice Wylde. The Wylde barely altered the chamber dimensions to accommodate the pressures created by each 5.56 NATO and .223 Rem. ammunition. Additionally, regardless of the warnings, many shooters freely shoot 5.56 NATO ammunition out of their .223 Rem. chambered rifles with out situation. OL Employees Author, Tyler Freel, discusses this in his intensive evaluation of the finest 5.56 ammo and .223 ammo check. If you wish to hearth 5.56 NATO ammo by your .223 chamber, proceed fastidiously and look ahead to any extreme strain indicators. In case you’re shopping for a brand new gun or barrel, you’ll be able to get rid of any potential ammo and strain points by buying a .223 Wylde or 5.56 NATO.

Ballistics

Evaluating ballistics between the 5.56 vs .223 reveals solely small variations. To check apples to apples, I chosen two manufacturing facility hundreds from Winchester, each of that are loaded with a 55-grain FMJ projectile.

A snippet of .223 ballistic knowledge (high) and 5.56 ballistic knowledge (backside). Winchester

Winchester 223 Rem. 55-grain FMJ

Muzzle Velocity: 3240 fps
Power @ 300 yards: 552 ft-lbs.
Drop @ 300 yards: 11.4 inches (with 100-yard zero)

Winchester 5.56 NATO 55-grain FMJ

Muzzle Velocity: 3270 fps
Power @ 300 yards: 612 ft-lbs.
Drop @ 300 yards: 10.7 inches (with 100-yard zero)

Nevertheless, muzzle velocity and downrange power will range relying in your bullet choice. Projectile weights range from 35 grains on as much as 85 grains with 55- to- 62-grain bullets being the preferred. For comparability, I chosen ammunition loaded with mild, mid-weight, and heavy bullets to spotlight variations in ballistics and the flexibility of the 2 cartridges. 

Hornady 223 Rem. 35-grain NTX Superformance

Muzzle Velocity: 4,000 fps
Power @ 300 yards: 411 ft-lbs.
Drop @ 300 yards: 5.3 inches (with 200-yard zero)

Nosler 223 Rem. 55-grain Ballistic Tip Varmint Ammunition

Muzzle Velocity: 3,100 fps
Power @ 300 yards: 533 ft-lbs.
Drop @ 300 yards: 7.7 inches (with 200-yard zero)

Barnes 5.56 NATO 85-grain Precision Match

Muzzle Velocity: 2,600 fps
Power @ 300 yards: 745 ft-lbs.
Drop @ 300 yards: 11.5 inches (with 200-yard zero)

These three ammunition choices paint a precious image for understanding the variations in muzzle velocity and downrange power that’s obtainable with the .223 Rem. and 5.56 NATO cartridges. 

Recoil

Recoil, or the dearth thereof, from these two cartridges is considered one of their greatest promoting factors and tremendously aids their reputation. The overwhelming majority of 5.56×45 ammunition produces between 5 and 6 ft-lbs. of recoil. In easy phrases, the recoil produced from these two cartridges is negligible. This permits shooters to remain heading in the right direction, watch bullet affect and make fast follow-up pictures if essential. 

Accuracy

A 30-shot group with .223 ammo. Photograph by Tyler Freel

Each the .223 Rem. and the 5.56 NATO are able to delivering distinctive accuracy. With that mentioned, accuracy with these two cartridges can and can range relying upon your rifle and ammunition choice. One variable to at all times take into account when deciding on ammunition is your barrel twist fee. Most .223 Rem. and 5.56 NATO rifles sport 1:7 or 1:8 barrel twist charges, that are ideally located for stabilizing and taking pictures every thing from 50- to- 75-grain projectiles precisely. In case you battle to get lighter or heavier bullets to group persistently, there’s a excessive probability it has to do along with your barrel’s twist fee and never the ammunition.

Use our check of .223 Rem. and 5.56 NATO ammunition as a baseline when searching for the most effective ammunition for these two cartridges. 

Terminal Efficiency

In the case of evaluating the 5.56 vs .223, each pack a lot punch to ship sufficient terminal efficiency in a wide range of searching pursuits. Nevertheless, given the small diameter and bullet weights, hunters should take heed to the cartridge’s limitations in searching situations. With a well-constructed bullet, corresponding to Hornady’s 50-grain monolithic CX bullet or Nosler’s 70-grain Accubond, hunters can confidently take down deer-sized sport at affordable ranges with the .223 Rem. and 5.56 NATO. Shot placement is essential, particularly when taking pictures small projectiles. These cartridge and bullet combos are perfect for recoil shy and first-time hunters.

Whereas the .223 Rem. and 5.56 NATO are a lot succesful within the deer woods, they actually shine within the varmint searching world. Not like the bullets essential for taking down a deer, nearly all of varmint searching projectiles are designed to penetrate the skinny pores and skin of a coyote or fox and inflict huge quantities of inside trauma. The result’s dead-on-impact hits that not often require a monitoring job. 

Ammunition Availability and Choice

Shopping for ammo in bulk usually helps save money in the long term. Photograph by Tyler Freel

Ammunition availability for the .223 Rem. and 5.56 NATO has been hit or miss over the previous a number of years, however now producers produce copious quantities of ammunition for these two cartridges. No less than in the mean time, 5.56 and .223 ammo is available each on-line and in most sporting items shops.

The price of .223 Rem. and 5.56 NATO ammunition varies relying in your meant use. In case you are simply seeking to plink metal on the vary, low-cost M193 full steel jacket ammunition may be bought for as little as $13.00 per field of 20. On the flip aspect, ammunition loaded with premium searching and match bullets can run upward of $60.00 per field of 20. 

Not like many different cartridges, 5.56 and .223 ammo is commonly obtainable in bulk. Most main ammunition corporations bundle 5.56 ammo that may be bought in case portions of 200, 500, or 1,000 rounds. Shopping for in bulk sometimes saves you cash in the long term.

Learn Subsequent: Coyote Cartridges: .223 Rem. Vs. .22-250 Rem. Vs. .243 Win.

Last Ideas on the 5.56 vs .223

Whereas the .223 Rem and 5.56 Nato are related, it is vital for gun homeowners to coach themselves on the nuances of each cartridges and at the least concentrate on the distinction in chamber pressures between the 2. In case you select to shoot 5.56 NATO ammunition by a .223 Rem. chambered rifle, you will need to vigilantly look ahead to any and all indicators of extra strain. No matter your taking pictures pursuits, everybody ought to personal a rifle chambered in a single (or each) of those cartridges. They’re sensible and able to every thing from searching to private protection. Plus, they’re downright enjoyable to shoot.