Ask the Community

Yes unofficially they are interchangeable and they will fire BUT if your gun is .223 specific or 5.56 specific only , then you may have problems with either calibers, again they will fire etc. But not optimally, most AR's made today are multi-caliber so should not be a problem. Check the link for a more detailed description of what I mean. https://www.hornadyle.com/resources/le-faq/what-is-the-difference-between-556-nato-and-223-rem-ammunition I would contact the manufacturer of the upper or the rifle you are using if you want to be absolutely sure.

Orin, yes Sir. Any 5.56 chambered AR will shoot 5.56 and .223 no worries. Cheers and stay safe!

Orin, as long as your gun is chambered in 5.56 then yes you can shoot either 223 or 5.56. if your gun is chambered for 223 then you can only fire 223 threw it. 5.56 has a higher chamber pressure and can cause damage if fired in a 223. Hope this helps.

Orin, if your barrel is stamped 5.56 you can fire either round. If it is stamped .223, you should not fire 5.56 from it. (you can, but you risk damage to your firearm and/or yourself). Most AR's today will shoot either one safely. Have a great day!