I try to plan out my purchases and now I'm back around to shotguns.

Here are some features that I would like. If anything like this exists please let me know.

Semi Auto with the shortest barrel available (can't remember if it's 16 or 18 inches before it becomes an SBS)

I want to be able to mount a light on it as well as a red dot and definitely a sling.

Obviously it's not going to be a duck hunting gun so the more capacity the better.

Any recommendations along those lines would help me to get started shopping around.