Hi Eric, that depends on the model. As long as the 930 cannot hold more than 5 rds in the magazine and does not have a pistol grip, it would be legal in Illinois. Either one of those features would disqualify it.
Illinois restrictions here -
budsgunshop.com/feeds/state_reg/illinois_restrictions.pdf ,
Stay safe & have a great day!

Hi Eric and welcome to the Buds Community. Just let us know the specific model you are looking at as some are and some are not depending on the exact specifications. The Buds 930 Illinois legal models are : budsgunshop.com/product_info.php/products_id/14634/mossberg+%26+sons+930af+12+3+28vr+accu+walnut --------------------------------------------------- budsgunshop.com/product_info.php/products_id/76743/mossberg+%26+sons+930c+12+18cb+28vr+accm+synthetic ------------------------------------------------- budsgunshop.com/product_info.php/products_id/46963/mossberg+%26+sons+930+field+12+ga+26+mossy+oak+bottomland+3+chamber ---------- Cheers and stay safe!

Here are the Specs for the
Mossberg 930 Field / Security Combo which would be legal in ILLINOIS. I'd personally go with this version due to the versatility of it.
Caliber
12 GA
Capacity
2.75 5+1
Features
Quick Empty Magazine Button, Sling Swivel Studs
Type
Shotgun: Semi-Auto
Action
Semi-Automatic
Finish
Matte Blue
Stock
Black Synthetic
Sight
Bead
Safety
Tang Safety
Receiver
Matte Blue, Drilled & Tapped
Chamber
3
Choke
Cylinder Bore and Multi-Choke (Full, Mod, IC)
Butt Plate
Vented Recoil Pad
Barrel Length
18.5 and 28 Por
Overall Length
39 and 48.5
Weight
7.5 lbs and 7.75 lbs
budsgunshop.com/product_info.php/products_id/76743/mossberg+%26+sons+930c+12+18cb+28vr+accm+synthetic...
What shotguns are banned in Illinois?
A semiautomatic shotgun that has any of the following features:
Pistol grip, or thumbhole stock.
Any feature functioning as a protruding grip that can be held by a non-trigger hand.
A folding or thumbhole stock.
A grenade launcher.
A fixed magazine with the capacity of more than five rounds.

Eric, depends Wich one your looking at. The Mossberg 930 is semi automatic so some restrictions do apply. It can't hold more than 5 rounds. Some hold 7+1 and aren't legal but some hold 4+1 and are perfectly legal in Illinois. It can't have just a pistol grip with no stock, can't have more than a 5 round fixed magazine tube, and can't have a thumbhole stock, collapsible/telescopic stock, or folding stock. If you post again with the model number or upc we can let you know for sure. You can find the model number and upc under the products description. If interested here's a link to one that's legal in Illinois..................... budsgunshop.com/product_info.php/products_id/76743/mossberg+%26+sons+930c+12+18cb+28vr+accm+synthetic ....................... Here's a link to another one that's legal.............................. budsgunshop.com/product_info.php/products_id/46963/mossberg+%26+sons+930+field+12+ga+26+mossy+oak+bottomland+3+chamber ........................ And there's one more on buds that's legal, link here....................... budsgunshop.com/product_info.php/products_id/14634/mossberg+%26+sons+930af+12+3+28vr+accu+walnut ....................... All 3 are perfectly legal in Illinois. All the ones on buds website I'm seeing that have less than 5 round capacity are legal but if you're looking at a specific one feel free to post with the upc or model number and we can let you know. Hope this helps.