Yes you can. I took a Remington 243 and put a 223 barrel on it. I also had to buy a new bolt with a 223 face on it, so I know it can be done. However, it would have been cheaper to buy a new 223, and it wouldn't have taken as long.I have had a Remington 700 SA 308 bolt face that i have a Remage. Im wanting to get a 223 bolt and use it for a 223 build for awhile. Can i just headspace the 223 bolt to the 223 barrel ?