[Pessimist]

I’m mainly a handgun guy, but isn’t there a technical error in this article?

I thought the military shot 5.56, not .223. If I understand correctly (big if), you can shoot .223 in a 5.56 weapon, but not the other way around. Something about the radius on the neck of the bullet or some such thing.

No?

[The Electrician]

While your statement is on target (sorry for the pun), as the SAAMI-specified maximum pressure in the 5.56mm round exceeds the allowable maximum for .223, and there are some dimensional differences, I wouldn’t call it a technical error - rather the author is speaking in generalities rather than specifics. Just as the author mentioned .308 Winchester instead of 7.62mm NATO.

[marktwain]

“I thought the military shot 5.56, not .223. If I understand correctly (big if), you can shoot .223 in a 5.56 weapon, but not the other way around. Something about the radius on the neck of the bullet or some such thing.”

---

No. 5.56 and .223 are pretty much interchangeable. If anything, it tends to work the other way. 5.56 has certain specifications that .223 does not. So, .223 may not function quite as reliably in military firearms as 5.56. In practice, a firearm chambered for one will shoot the other.

[Nebr FAL owner]

They are basily identical .223 is the inch diameter 5.56mm is the same thing only in metric measurement