What is the rifle? I believe that most Russian surplus ammo is 0.221", and that is the barrel that they run on the AK-74 rifles. I would not be surprised if ar-15 uppers made in the US have a 0.224" bore, but don't actually know. I bought some 60 gr v-max blem bullets for my 223 that are undersized to give a 0.221" diameter. If you are interested I would sell them to you for pretty cheap. Let me know.