IL is shotgun slug for deer.
you can use any rifle cartridge for coyote and small game etc...
I'm pretty certain you can hunt coyote 24hrs a day and any size magazine... kinda odd compared to deer season/slug.
I believe I read an article on how slug gun states tend to have bigger bucks...
I think you can use muzzle loader for 2nd deer season now.
I think the theory at least is, guys won't take 500yd shots and wound deer with a slug... 100yds is pretty far to most sluggers and probably 200 is close to the upper limit.
Also less chance of wounding a fellow hunter with a rifle bullet vs slug.