I ran into this problem with my CZ527 Kevlar as well. It wasn't shooting well. It also has a 1:9 twist barrel at 24". Some reading and this wasn't uncommon. Seems the barrels for that rifle preferred lighter loads. I had some 52 Berger's around and varget so loaded some up. Not spectacular but around 1 moa. Much better than what I was getting from heavier accuracy rounds. More reading and apparently 45 hornady is a tack driver in these rifles. Sometimes you just can't tell what the barrel will favour. There may also be some heavier combinations that work great. But as it's a varmint rifle I'll stick with the lighter stuff.
Read up on the specific rifles and reloading. There's usually a trend with what they favour. Work around that.
Hey Epoxy~thanks for the reply. Funny, I had myself so convinced the heavier stuff SHOULD be shooting well that I hadn't even considered buying bullets lighter than 55gr. A friend of mine from (from CGN) PM'd me back when I was doing the load testing and told me he was getting great results from 53s in his Savage. (same twist) Indeed, they shot the best but since I'm a little slow to see the obvious...I've been wondering IF lighter loads might actually shoot any better/any different. It's printing very small groups with the 53s...but I'm a tinkerer, so I might try even lighter.