I recently purchased a Remington 1187 .12 Gauge shotgun, and I want to be able to shoot slugs, for whitetail hunting. I'm new to the shotgun world so I was wondering what process or steps I need to take to make it able to shoot slugs.

I used my 11-87 for deer hunting for a few years and even have a real nice buck on the wall that was shot with it. When I used mine I just shot Brenneke rifled slugs through the imp. cyl choke tube. This was not a long range set up. Usually my shots were 50yds or less. If you really want to get serious you'll probably want to put a rifled barrel on it and shoot some type of sabot slug.

What NCZ stated is about what you'll have to do to shoot rifled slugs through the smooth shotgun barrel and normally an open choke like he used is the best. Most will tell you not to use a real tight choke to shoot rifled slugs. The other way to go is to buy a slug barrel that is rifled and designed to shoot sabot type slugs. Most of them will have the ability to mount a scope on it and then you just need to try different sabots to see which shoots best through that barrel.