I had hunted with an 870 for about 15yrs before I gave it away. The first thing I would do is get a limbsaver or kick-eez pad installed on it. That will help out your shoulder. As a slug gun I found itvery accurate,buthigh quality steel rings like Warne and a tough scope is a must. Check out the Bushnell Dawn to Dusk shotgun scope series. Many gun shops and big stores like Gander Mountain willmount and bore sight the scope for you. If that's a rifled slugbarrel, keep in mind it was designed to shoot sabotedammo. You can shoot Foster slugs or bore size slugs, but it will lead up the barrel badly, and it won't be nearly as accurate.