From exp, an 11000 magnum will be picky about the loads it shoots at least in 20. mine turned into a slug gun.
I had an older 12Ga. Magnum that belonged to an old duck hunter. This 1100 ate everything it was fed. One time, just to prove a point, I loaded it with a variety of alternating shotshells. It cycled just fine. I took more deer with it than anythig else I shot. Sold it to my buddy's son and he took three deer with it, this year .....
Be Safe !!!