Hi Stan, this is not Illinois compliant due to the pistol grip.
"Assault weapon" means any of the following:
A. A semiautomatic rifle that has the capacity to accept a detachable magazine or that may be readily modified to accept a detachable magazine, if the firearm has one or more of the following:
❌ i. a pistol grip or thumbhole stock;
budsgunshop.com/feeds/state_reg/illinois_restrictions.pdf

Hi Stan and welcome. It will accept S&W M&P Magazines. It, however, is not legal for sale in IL due to the Pistol Grip. Buds will not ship, if they would, you could add this kit to be compliant: keltecweapons.com/product/sub2000-featureless-kit/ ----------------------------- https://support.keltecweapons.com/how-to-install-sub2000-featureless-kit