a 24" barrel on a .223 will give a 50 grain bullet a lot of velocity -- maybe 3350fps or so, but still much less than a 40 grain bullet. The rotational velocity of the 50 may be (probably would be) slow enough out of a 1 in 9" bore to allow the bullet to hold together. The 40 grain bullet might get 3600fps and with a 1 in 8" would possibly come apart.
I'd slow down the rotational velocity with a 1 in 9 twist and with a medium(?) weight bullet.
The one-inch thick barrel I see as a plus.....regarding potential stability. The semi-automatic action of the rifle is what will probably most compromise its accuracy, since they are more loosely chambered and the bolts don't lock up as tightly.
Good luck.