Try the
Hornady loads for hunting Yotes...( I like the 55 and 62 grain the best )
http://www.hornady.com/store/223-RemThe
1:9 is a great compromise twist rate—not too fast to cause problems with the 55-grain Bullets, but fast enough to stabilize all but the heaviest bullets under most circumstances. This twist will stabilize most traditional bullets up to 75-grains, and monolithics up to 70-grains—but they do so right at the
edge of the envelope so not all rifles will do it.
My personal 16-inch Rock River Arms carbine ( 5.56x45mm ) with a 1-in-9 twist does fine with the heavier Hornady 75 grain BTHP load, but has shown signs of instability with
handloads using the 70-grain Barnes TSX—unless the bullet is pushed to maximum velocity. With longer barrels and the commensurate faster velocities,
this twist can be more forgiving.