These are what I run in my M4-11703 with a Tru-loc breacher choke (cyl) and aimpoint T-1
Slugs: Winchester power point, a one ounce slug @ 1700 fps.... shoots one big hole @25yds.....no feeding problems.
Buckshot: Fed 132 00, the flight control gives a tight group @ longer range, and no feeding problems
My newest test shell: Winchester PDX1 Personal-defense, three 00 buck atop a one ounce slug. The slug hit dead center with the 00 forming a triangle about three in. from the center on a target I saw. Cabela's has this shell for $13.00 per 10.
YMMV