I've had a .223 UV for a year and won't part with it. A little sticking when I first bought it; I took the end of a cleaning rod and a piece of coarse cloth and polished it in front of the TV for about 30 min. -- no more stuck cases. Best factory ammo is Win 45 JHP valu-pack and Ultramax 40 & 50gr V-Max. Handloads are 50gr Nosler BT with 26gr Varget. This rifle will shoot 1 to 1.5 MOA on a bad day, and close to 1/2 on a good one. I've had 1 1/4" groups at 200yds and 5/8" at 100 from time to time. Accuracy can vary from rifle to rifle, but once you find a load that works, you'll be happy.
If you shoot from a bench, one trick a lot of people find useful is to rest it on the hinge, not the forestock. Makes a big difference in mine. And stay with lighter bullets; 55gr or so and under. The H&R .223 has a slowish 1:12" twist, and won't typically stabilize heavier bullets. I may try some with handloads sometime. Occasionally people have luck with 62gr, but most heavier bullets come out sideways.