hannah, I have had very good luck with the S&B 55gr. FMJ in my .223UV. I have put thru more than 200 rounds after initial break-in and I have shot many moa and a few sub-moa groups @ 100yds. My reloads perform better, but for factory the S&B does very well for me and my rifle. It is a 1-12 twist. I also have had success, like many others, with the WWB hp's when they were available. I have also reloaded the S&B brass with good results.
Good luck and have fun!