That is a good question, lemme break out my scale and find out.
Weighed on my Rapala Digital 50# fishing scale.
Empty, no mag: 9lb 3oz
MD20, loaded with Winchester Military, 00, 9 pellet: 13lb 3oz
SGM 10rd, Winchester Military, 00, 9 pellet: 11lb
Factory 5rd, Fiocchi, #4 buck, 24pellet: 10lb...