Where do you stand on this? The only place I see the 24'' have the advantage is at 400+ yards, because that's when FPS starts to really matter with a .223. I'd like to be able to take the rifle out to 600 accurately (I'd be happy with a .75 to 1 MOA group at that distance) and be in the neighborhood at 700. I'm trying to avoid going trans-sonic.
Bushmaster states a 100 FPS difference between the two with factory ammo.
What I'm really comparing buying for my build is the 1/9 twist 24'' varminter barrel by Bushmaster or the 1/8 twist 20'' Predator barrel by Bushmaster. Neither of these are chrome lined, but that's okay with me.
I've heard that with some loads in .308 that there is practically no velocity gain in a barrel longer than 20''. Can this be done with .223? I'm a reloader, so I can switch to whatever powder is needed to get a burn rate to achieve maximum velocity in 20'' instead of 24''.