The AK-47 is chambered, primarily in 7.62X39. The AR-15 is mostly chambered in 5.56X45.
There is a difference between 223 and 5.56.
If we are talking about .223 Remington SAAMI-spec chambers in an AR15, OH NO!
Do NOT use such a chambering if you EVER plan on shooting any military NATO 5.56 ammo, which happens to be only the most common, least expensive and most widely used AR15 cartridge available in all the world. In other words, NEVER buy/use a SAAMI-spec chamber in a battle rifle, especially if the barrel and chamber are chromed, as you cannot fix it!
Here's the problem. Many NATO cartridges have bullets that will become jammed into the rifling of a SAAMI chambering (the throat is too short). This is VERY DANGEROUS, for a grat number of reasons.
Fulton Armory uses a "5.56 Match" chambering in its rifles/uppers/barrels, which is a slightly modified SAAMI chamber with a tad longer throat to accommodate NATO bullets. The Fulton Armory 5.56 Match chamber allows for the safe and reliable use of all SAAMI and NATO ammo, while offering the accuracy potential of the SAAMI chamberings with match commercial cartridges. Remember, there's often a large difference between bolt guns and military rifles. This particularly true for the 5.56 vs .223; Fulton Armory is well known for the finest performance for any given platform.