Good job on the target and great idea with the caliber. I built one on a S&W upper chambered in 5.45x39 as well and it's a great little gun. The ammo is becoming a little harder to find, but it's still priced way better than .223. I kept my AK-74, though. I guess my idea was to keep some similarities in caliber between firearms so I don't have to stock up on 10 different kids of ammo...... also upgraded my trigger too. Nice work!