Typo, meant to type 1100 ft pounds
Still a big deficit. The nominal baseline for a 2.75” 1 ounce foster slug is in excess of *2300* ft-lbs. A 3” cartridge 1 ounce slug generates in excess of *3100* ft-lbs. By comparison, a 150 grain .30-06 bullet generates about 2200 ft-lbs of muzzle energy.
Going with a short mini shell gives up a *lot* of the raw power that is the shotgun’s short range advantage.