A stick/extruded powder in the speed range of H322 would do well. Stay away from ball powder; its track record for best accuracy is not all that great. Best accuracy means no worse than about 3 inches at 600 yards or about .3 inches at 100 yards.
That 1:9 twist is best for bullet weights around 70 grains; may be too fast for 55 grain bullets. So I suggest staying away from max loads with 55's and use reduced ones.
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