it is a smoothbore so you would need to use foster type "rifled" slugs and they are effective to around 70 yards you accuracy at 100 yard would not be acceptable for hunting to hunt deer at 100 yards with a shotgun you need to go with a rifled barrel and sabot type slugs A smoothbore "slug gun" with rifle sights will usually shoot groups in the 3" (6 MOA) range at 50 yards/meters, making them satisfactory deer hunting weapons at short range.

Hi Phil, with a 18.5" barrel, you mat lose accuracy at 100yds. I would not go more then 50-75 yrds with 18.5" barrel.
You can always test it at 100 yds, but don't count on accuracy.
Stay safe & have a great day!

Hi Phil and welcome. It will work no issue for deer hunting. You will get the best 100-yard accuracy with Foster Type Rifled Slugs. budsgunshop.com/product_info.php/products_id/63488/federal+pb12dprs+premium+vital+shok+12+ga+2.75+1+oz+truball