Hey there everyone, just joined the forum. I hope this question isn't a dumb one but I haven't got an answer for it. I know the difference between 223 & 5.56 but when I look to buy ammo online I often see the ammo lable listed as "223/556" so my question is which one is it? The ammo I have purchased online in the past was specifically listed as one or the other but I commonly see ammo sold as "223/556" so I'm not sure which one it actually is. Again I hope this isn't a dumb question but I am curious. Thanks and look forward to the replies.