I just ordered an AK-74 derivative that's chambered 5.56x45mm NATO. The wife would not have liked the higher recoil of 7.62x39 that was my original plan... Now it's time to buy some ammunition. I can safely use .223 Remington round as well and these seem to be more widely available than 5.56x45 rounds. The gun will be sitting under the bed in case of emergencies but I envision that the shotgun will retain that duty. It's mainly going to be for fun at the range. Any potential downside of going with .223?