I have an AAC Single Shot with a 1/7" twist. It shoots anything 150 and heavier great but anything less, it shoots about 3-4". I swage a 250 boattail that will shoot an inch or a bit better at 100 out of the little thing. Another interesting load is Speer 150 Hot Cores with a top load of Shooters World Socom. Shoots about an inch at 2100 fps. No joy with cast bullets of any weight.
I experimented with all sorts of things to get the 250's to expand at subsonic speeds including pre-fragmented cores, hollow points, etc. They have a huge lead tip. No significant expansion with anything I did. The Hornady 190 grain factory ammo expands a bit and shoots pretty well.