BudsGunShop.com - slug barrel

Shannon, yes they do. >>> winchesterguns.com/products/accessories/shotgun-barrels/sxp-extra-barrels/sxp-rifled-barrel-matte.html

yes they do make a slug barrel contact winchester r Customer Service number at (800) 945-5237 or (801) 876-3440. If you need help with Parts and or Service, please call (800) 322-4626.

Found one in stock here
tactical-store.com/ts-wq-bsg-w611261340.html

Yes they make them but they don't seem to be in stock anywhere right now.
I would hit the "notify me when available" button to receive an email when they come back in stock
budsgunshop.com/product_info.php/products_id/713076383

Shannon, yes Winchester does make a Rifled Slug Barrel - winchesterguns.com/products/accessories/shotgun-barrels/sxp-extra-barrels.html