I tried some 12ga 3in Winchester BB loads in a couple of 20in, IC, Rem 870s a while ago, was fairly impressed. Used a 24 in square piece of paper as target, the pattern put almost all the pellets in the 24in paper and was very even. I'd think it would be deadly out to 30 yds, maybe more with right shotgun. Center on a coyote and you'd have holes nose to ass.
Also tried some 2.75 in Rio 4 buck and Win 1 buck same day. Similar results, about a 18- 24 in pattern at 25 yds, just a lot fewer pellets.