Can a 5.56 Rifle Shoot .223 Ammunition? Vice Versa & Everything Else You Need To Know

Before we get into this article, for the sake of safety, use the designated ammunition stamped on the barrel of your firearm. This will ensure the longevity of both your rifle and your face.

One of the most commonly asked questions that firearms owners and those in the tactical community want to know is whether or not their rifle can shoot both 5.56 NATO and .223 ammunition. Because of the near identical similarities, you might think that these rounds are interchangeable with either rifle. In this article, I’m going to be answering the question if whether or not a rifle chambered in 5.56 NATO can shoot both 5.56 NATO rounds and .223 Remington rounds, and then explain why or why not.

So, can a rifle chambered in 5.56 NATO shoot a .223 bullet?

Yes, a .223 Remington bullet can be fired safely from a rifle chambered for 5.56 NATO. The reason for this is because 5.56 rounds have a higher chamber pressure at around 58,000 psi compared to the .223 Remington which has a chamber pressure around 55,000 psi. So the rifle chambered in 5.56 NATO will be able to withstand the .223 Remington ammunition.

Something to keep in mind is that because of the lower pressure in the .223 Remington round and the longer throat in the rifle chambered in 5.56 NATO, it reduces the internal pressure even more. This can cause cycling issues, especially for rifles with less than a 14.5” barrel length. It needs the longer barrel length to create enough back pressure to cycle the rifle properly. This is not a safety issue though, and this shouldn’t happen too often. But if you’re having cycling issues, then this could be the reason why. That said, you should always use the ammunition that the rifle is chambered for.

So can a rifle chambered in .223 shoot a 5.56 NATO round safely?

It depends. A rifle chambered for .223 Remington would not be able to shoot 5.56 NATO ammunition safely, for a couple of reasons. The 5.56 chamber has a longer throat in the chamber by approximately 0.125″. Because of this, you can have the bullet out more allowing for one more grain of powder. So because a 5.56 NATO round was designed to fit inside a rifle chambered in 5.56 NATO, when you load that 5.56 NATO round into a rifle chambered in .223 Remington, the projectile will be pushed against the rifling of the barrel. So even though the pounds in pressure may be very close, the lack of space inside the rifle chambered for .223 Remington doesn’t allow the gases to escape, which can create pressures of up to 65,000 psi inside the chamber. That being said, there is a caliber designation for .223 that is able to withstand the higher pressure of the 5.56 NATO round, and that is the .223 Wylde.

Does the 5.56 NATO and the .223 Remington use the same projectile?

Yes, the 5.56 NATO and the 223 Remington use the same bullet projectile. If you look closely enough, you can see an engraved knurling on the side of the bullet. This is to show the difference in length of throat between the 556 NATO and the 223 Remington.

How accurate is the .223 Remington?

Accuracy is dependant on a multitude of factors. So many that I won’t list them all. Generally, if you’re using a semi-automatic rifle and firing .223 Remington, you’re going to have a grouping around 1.5 – 3 MOA. If you’re using a long-barrel bolt-action weapon system with the right ammunition, then you’re likely going to have a sub-MOA grouping, and even a sub-half-MOA grouping.

What is the effective range of 5.56 NATO ammunition?

During my time serving in the Armed Forces, the rifle we used fired 5.56 NATO ammunition, and we were usually firing from 200 meters. Occasionally we would start at the 400m line, run to the 300m line, lay in the prone position and begin sending rounds on target. Then we would run to the 200m line and take some more shots on target, run again to the 100m line for more shots on target, eventually taking it to the 25m line, dumping ammo in full automatic.

From 200 meters, we would be expected to hit the target in the standing position. Of course the grouping would be terrible, but the 5.56 NATO round is very effective between 200 – 300 meters. All of this depends on the ammo you’re using, the weapon system, the optics, and other factors. In the right conditions, with the proper setup, and the best equipment, 5.56 NATO ammunition could be effective between 800 – 1000 meters.

Conclusion

As I stated at the beginning of this article, use the ammunition that is stamped on the barrel of your firearm. Yes, you could use .223 Remington in a rifle chambered for 5.56 NATO, but to have the most effective results you should stick to using 5.56 NATO rounds. If you use 5.56 NATO ammunition in a firearm chambered for .223 Remington, it could be harmful to your firearm and can have catastrophic results. Reason being is the excess of pressure built up.

Don’t forget that a firearm chambered in .223 Wylde can safely and effectively shoot both 5.56 NATO and .223 Remington ammunition.

This writeup was shorter, but I hope it’s been helpful to you.