9 twist barrels, as noted above, work fine for heavier .224 bullets.
After lots of experimentation I found that 75-77 gr bthp match bullets with 24-24.5 grains of several good powders (including Varget, RE15, H4895, VV N140) does really well. After many thousands of rounds in testing and competition, I am not really excitable about which of the combinations is THE Best.
Most all of my bolt guns, and all of my space guns, will get a half MOA with nearly any of them.
Since I'm shooting at one MOA x-rings, I virtually never have to blame low scores on the ammo. Once I figured out that all the ammo shot better than I do, I quit wasting a lot of my time and spent more time in practice.
You will get slightly better performance with one or the other, depending on your barrel, but most of them will do quite well.
Just my two cents.
Good luck.