Per http://www.omahamarian.org/trap/shotshellenergy.html

20g 7/8 oz. 2 1/2 Dr. Eq. = 1210 fps in a 5.75# gun = 19.1 ft. lbs

20g 1 oz. 2 3/4 Dr. Eq. = 1220 fps in a 5.75# gun = 23.9 ft. lbs. recoil

12g 1 1/4 oz. 3 1/4 Dr. Eq. = 1220 fps in an 8# gun = 25 ft. lbs.