Originally Posted by MontanaRifleman
I agree. I know there's a lot of guys who like shooting the lighter bullets and the high velocities and that's fine. With a factory twist of 12-14 you have to shoot the lighter ones and probably won't be able to shoo the 70 gr bullets. I am getting mine re-barreled to an 8" twist to shoot the high BC 80's. But, if your set on shooting the 70's go with the 22-250.
Fast twist barrels also have their own issues, as I've came to learn. The big over bore cases can also have their own issues as well. Plus they're a little harder to develop loads. Plus, don't believe the specs that some bullet manufacturers will tell you for the needed barrel twist. Then you decide to shoot a bullet with a B/C in the low to mid point fives. You select a barrel with the needed rate of twist. But later decide to shoot bullets of a dog town in the point three B/C area. Bullets don't group as well because your over stabilizing them. But slowing them down helps, but you want to shoot them fast and flat. And we already know what happens when you try to shoot a high B/C bullet in a barrel with too slow of a twist. Every barrel has a window of bullets it will shoot well.
In this case the O.P. should set down and think first about what he's going to do with the rifle. Is he going to hunt deer or maybe even antelope? Elk or moose? Or is just for varmint shooting. Then you have to consider the ranges your planning to shoot at. 95% of the guys hunting will not be shoot deer at 500+ yards, but an antelope hunter might be.
A basic 22-250 with a nine twist barrel is still done at 500 yards, while the same round in a twelve twist is pretty much done at 400 yards. A 6mm whatever is not going anywhere past 400 yards with a 75 grain bullet, but change over to an 85 grain and we're looking at 500 yards. The 105 Amax will
will do 650 yards, and maybe a little more. The 6mm bullets (heavier versions) compared with the bigger bullets in a .224 have over 20% greater sectional density. The 25 calibers are similar to the 6mm's, but these two diameters usually have heavier jackets. This is better for hunting deer sized game and up. On the otherhand a ground hog won't ever know the difference.
There really is no do it all caliber. The .223 bore is better for dog towns, as it won't beat you up. But when the ranges stretch out the 6mm moves up front. But after a hundred rounds they do get a little old. For coyotes you'll never notice this. If you choice of targets runs from ground hogs out to deer, the 25 is always going to be better even though the 6mm does very well. But of course you could move up to the 6.5's, and seriously gain range and power. A .250AI with a ten twist barrel and a 117 grain bullet will be right at 3000fps, but will still shoot the 75 grain bullets well. That's a little more power than most 6mm's shooting the 105 grain bullet, but will also have a heavier bullet construction.