Thanks for the replies. I had not even considered the length/style of bullet. I have all these 55 grs as my AR is a 1:9.
The Weatherby 1:12 shoots them pretty well but I wanted to try to tighten it up a little more. I will have to go to a different range(crazy public range

) to shoot over 100 yds as that's all we have at my current range(private).
I need to place an order for other "stuff" so I'll order a box or two of some premium bullets.
I also found this site which has a lot of good info. These guys are in a different league than I am.
223 Rem + 223 AI Cartridge Guide
Edit: After re reading some of the replies, I might actually be better with a lighter bullet??