Well, if you consider shotguns with rifled barrels to be rifles, then for Illinois:
20 Gauge Slug Gun (Savage 220)
Bolt action or AR in 5.56/223
If you don't have to count the shotgun and ammo cost barrel life DOES matter:
22lr in whatever action type you want
Bolt action or AR in 5.56/223
If ammo cost and barrel life doesn't matter:
22lr in whatever action type you want
Bolt action .22-250
IF Illinois ever moved to allowing straight walled cartridges for deer, that would make things alot more interesting. It's been proposed/discussed but never gotten through.
Actually, interesting workaround for deer hunting with a "rifle"... as understand it, you can use an AR PISTOL in an appropriate cartridge if you use a single shot "bob sled" insert in the magwell to make it single shot. The requirement for revolvers/handguns is:
-Centerfire revolvers or centerfire single-shot handguns of .30 caliber or larger with a minimum barrel length of 4 inches.
- For handguns, a bottleneck centerfire cartridge of .30 caliber or larger with a case length not exceeding 1.4 inches, or a straight-walled centerfire cartridge of .30 caliber or larger, both of which must be available as a factory load with the published ballistic tables of the manufacturer showing a capability of at least 500 foot pounds of energy at the muzzle. Note: There is no case length limit for straight-walled cartridges.
Reading around, multiple people have gotten clarification from DNR that such a setup falls within regs and is GTG. 300 BLK is popular for such setups, I imagine 350 Legend will probably pick up some steam as well. With straight walled cases not being limited in length, I'm sure you could go with some more interesting/powerful calibers as well especially if you bump up to an AR-10 setup. If I ever really get into deer hunting, I may very well go that route as it is a more multipurpose setup.