The short answer is “no,” but there’s a little more to it than that. The 223 Remington and 5.56 NATO cartridges are very similar, but they are not exactly the same. The 5.56 NATO cartridge is a little longer, has a little more powder, and produces a little more pressure than the 223 Remington cartridge. For this reason, you should not use 5.56 NATO ammunition in a 223 Remington rifle.
The 223 Remington and 5.56 NATO cartridges are both popular choices for self-defense, hunting, and target shooting. They are both accurate and powerful, and they can be used in a variety of different firearms. If you are unsure about which cartridge to use in your firearm, it is best to consult with a gunsmith or other expert.
Advance Tips: Are 223 And 5.56 Interchangeable?

223 and 5.56 are not interchangeable. The 5.56 is a military round that is not intended for use in civilian firearms. The 223 is a civilian round that is not designed for use in military firearms. There are many differences between the two rounds, including the dimensions of the bullet, the amount of powder in the cartridge, and the pressure at which the cartridge is fired. While it is possible to fire a 223 in a 5.56 firearm, it is not recommended and could result in damage to the firearm or serious injury to the shooter.
The 5.56mm NATO round was developed by NATO in the late 1950s as a standard small arms ammunition. It is derived from the .222 Remington, a varmint round used for hunting small game. The 5.56mm NATO has a bullet diameter of 5.70mm and a case length of 39mm. The powder charge is between 26 and 28 grains, and the cartridge is fired at a pressure of 50,000 psi. The 5.56mm NATO is used in a variety of military firearms, including the M16 rifle and the M4 carbine.
The 223 Remington is a civilian version of the 5.56mm NATO round. It was developed by Remington Arms in 1964 as a varmint round. The 223 Remington has a bullet diameter of 5.70mm and a case length of 38mm. The powder charge is between 22 and 24 grains, and the cartridge is fired at a pressure of 42,000 psi. The 223 Remington is used in a variety of civilian firearms, including the AR-15 rifle.
While the 223 Remington and the 5.56mm NATO share the same bullet diameter and case length, there are several important differences between the two rounds. The 5.56mm NATO has a higher powder charge than the 223 Remington, which means that it generates more pressure when fired. This difference in pressure means that the 5.56mm NATO round is not safe to use in a 223 Remington firearm. The 5.56mm NATO also has a different rifling twist than the 223 Remington, which can cause accuracy problems if the two rounds are used interchangeably.
It is important to note that while the 223 Remington and the 5.56mm NATO share many similarities, they are not interchangeable. Firing a 5.56mm NATO round in a 223 Remington firearm can be dangerous and could result in damage to the firearm or serious injury to the shooter. It is always best to consult the owner’s manual for your specific firearm to determine what type of ammunition it is designed to use.
223 Remington vs 5.56 Nato – Which is More Preferable?

When it comes to choosing a caliber for your AR-15 rifle, there are a lot of options to pick from. Two of the most popular choices are the 223 Remington and the 5.56 NATO. But which one is the better option for you?
223 Remington
The 223 Remington is a popular choice for AR-15s because it is a versatile caliber that can be used for both hunting and target shooting. It is also a fairly inexpensive caliber to buy.
Pros
- Inexpensive
- Versatile
- Accurate
- Low recoil
Cons
- May not be powerful enough for some big game animals
- May not penetrate thick brush as well as some other calibers
5.56 NATO
The 5.56 NATO is the military standard caliber for the AR-15 and is a popular choice for those who want a rifle that is suitable for both home defense and hunting.
Pros
- Powerful
- Accurate
- Low recoil
- Easily available
Cons
- More expensive than some other calibers
- May be too powerful for some small game animals
- May not penetrate thick brush as well as some other calibers
So, which is the better choice for you? It really depends on what you want to use your rifle for. If you just want a versatile all-purpose rifle that you can use for hunting and target shooting, then the 223 Remington is a good choice. If you want a rifle that is suitable for home defense and hunting big game animals, then the 5.56 NATO is the better choice.
How do they differ in size and shape?
No, 223 and 5.56 are not interchangeable. The two cartridges are of two different sizes and shapes. The 223 cartridge has a smaller case and a larger diameter bullet than the 5.56 cartridge. The 223 cartridge also has a shorter case length than the 5.56 cartridge. The 5.56 cartridge has a larger case and a smaller diameter bullet than the 223 cartridges. Additionally, the 5.56 cartridge has a slightly longer case length than the 223 cartridges. Therefore, even though these two cartridges are similar in caliber, they are not interchangeable.
What are the differences in the ammunition used for each
No, .223 and 5.56 are not interchangeable. .223 is a civilian round used in the popular AR-15 platform, while 5.56 is a military round used in the M16 and M4 platforms. The 5.56 round is more powerful than the .223, so it can be shot in a .223 chamber, but the opposite is not true. Additionally, the 5.56 round is designed to be used with a rifling twist of 1:7 or 1:8, while the .223 requires a 1:12 twist. As a result, it is not recommended to use 5.56 rounds in a .223 chamber, as it can cause excessive wear on the barrel or even jamming.
Frequently Asked Questions [FAQs]
223 is the civilian version of the 5.56 NATO cartridge. The 5.56 is a military cartridge with slightly different dimensions and pressure specifications.
Yes, you can use 223 ammo in your 5.56 rifle. The 5.56 chamber is slightly larger than the 223 chamber, so the 223 ammo will work just fine in a 5.56 rifle.
The 5.56 brass is slightly thicker than the 223 brass. The 5.56 brass is also military-spec and is not as widely available as the 223 brass.
Yes, you can reload 223 brass for use in your 5.56 rifle. The 5.56 chamber is slightly larger than the 223 chambers, so the 223 brass will work just fine in a 5.56 rifle.
The 5.56 bullet is slightly heavier than the 223 bullets. The 5.56 bullet is also military-spec and is not as widely available as the 223 bullets.
Conclusion
The quick answer is “no.” The two cartridges are not interchangeable. The 5.56 NATO cartridge is a military round that is not the same as the commercial .223 Remington cartridge. The 5.56 NATO round is loaded to higher pressures than the .223 Remington cartridge.

A. Wilcox Head is a lifelong shooter, hunter, and firearms enthusiast. Head grew up in a family where firearms were a way of life, and from an early age, he was taught the importance of firearm safety, accuracy, and proper hunting techniques.
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