Used my 870 with SSTs two seasons ago for deer. Shot a 200 pound doe right through the heart at 110 yards. She went 30 yards, massive blood trail, complete slug pass through, no blow out.

Shot a buck about the same size a week later at about 30 yards. Complete pass through at the shoulders. No blow out. Exit holes were about the same size as the entrance holes on both deer.

Seems like these slug have more than enough power, and hold together well.