BudsGunShop.com - Ammo?

That's a nice looking shotgun, after you throw a magazine tube extension on it anyways, bring it to 7+1+1 and that'd make a nice home defense tool.
To your question yes it'll fire slugs, Rifled (foster slugs) will get you the best range and accuracy as this is a smooth bore shotgun, and rifling on the slugs will help them shoot straight and not lose energy as fast. This shotgun has a 3"chamber so you can fire any 2¾" or 3" shells out of it, doesn't matter the size of the pellets (shot) it'll fire 000 all the way down to light target loads, but for a semi-auto id try to stick to 1200fps or faster, my Beretta 1301 runs really light loads though so just try em out and maybe it'll run clay shot (1100fps) too.
But no worries on the big heavy stuff it'll eat that up no problem

Kenneth, this will shoot both 2-3/4 inch and 3 inch shells. This will work well with bird shot, buck shot and slugs. Since it's a smooth bore rifled slugs will work best. Hope this helps.

Kenneth, yes Sir, this shotgun is capable of firing any standard 12 gauge shells including Bird Shot, Buck Shot and Slugs. Foster Type Slugs through Cylinder and a Max of Modified Choke for Slugs. I would test different brands and then stock up on what shot patterns best and what slug is most accurate in your shotgun. Cheers and stay safe!