223 Remington Vs 556 NATO Ammo: The Main Differences

Understanding the difference between 556 NATO and 223 Remington ammunition is crucial for choosing the right ammunition for your firearm to ensure safety and performance.

From the outside, these two appear to be very similar, almost identical. Someone with no experience will most likely try to interchange them, but this can have dicey consequences, and this article explains why.

But before that let’s run through a brief history of how each one of them came about.

The .223 Remington

This is one of the most popular cartridges in the world, which came about in the late 1950s. it’s mostly loved because of its availability, relatively flat trajectory, and low recoil.

Remington collaborated with Fairchild Armalite Corporation and their principal designer, Eugene Stoner, who developed the AR-15 rifle, to create the 223 Remington cartridge. It’s an advancement of the 222-round and has better ballistic performance.

The cartridge was designed to be used in the AR-15, which was later adopted by the U.S. military as the M16 rifle, chambered in 5.56 NATO.

The 5.56 NATO  

It was developed in the mid-1960s as part of an effort to provide the military with a more capable lightweight round. This was shortly after the 223 was produced, and what needed to be done was to use the .223 as a baseline.

To put it in simpler terms the 5.56 is a slightly modified .223 to cater to the military. The modifications include a thicker brass, and a slightly tapered and longer neck to facilitate easier extraction.

The cartridge can also accommodate more powder than the .223 which results in slightly more stopping power. It can also tolerate higher chamber pressure of 58,000 pounds per square inch(Psi), compared to 55,000 Psi on the 223.

So, What’s the Difference Between .223 Remington and 5.56 NATO?

The differences between these two ammunitions include;

Pressure Differences

The 5.56 NATO (5.56x45mm NATO) round is loaded to higher pressures than the .223 Remington. The maximum average pressure for 5.56 NATO is about 58,000 psi (pounds per square inch). The higher pressure of 5.56 NATO results in increased velocity and impact energy.

This also implies that it is not safe to fire the 5.56 in a chamber built for the .223, but the opposite is not true. Firing a .223 Remington ammunition in a 5.56 NATO chamber will result in lower pressure than the chamber can sustain, so doing it won’t be dangerous. But you’ll likely experience reduced velocity and possibly degraded accuracy.

Accuracy

The.223 has marginally better accuracy than the 5.56 NATO. This is because the 223 was developed with accuracy in mind, down to the chamber. The 223 chamber is tighter and has a shorter throat (leade), resulting in reduced pressure which helps accuracy.

In contrast, the 5.56 focuses on increased reliability in automatic and semi-automatic rifles, as well as terminal performance at engagement distances.

It is important to remember, however, that accuracy and velocity are affected by a multitude of other elements such as a shooter’s skill, barrel length, and the environment.

Cost of Ammo

Because the .223 is purposed for use by civilians it’s cheaper and readily available. The 5.56 on the other hand is built with military specifications and is generally expensive.

Conclusion

The 223 Remington and 5.56 NATO cartridges share many characteristics, such as recoil, although they differ in pressure, chamber size, and accuracy.

The 223 is often used for precision shooting, whereas the 5.56 is regarded for its dependability and increased pressure, which result in a bit more stopping power, making it suitable for tactical and defensive applications.

Because the 5.56 chamber can accommodate a.223, it is more versatile and should be a better value.

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