Cut shells, bore obstructions, steel shot through a full choke, these are all the same thing to different degrees. Knowing that you can cut a shell and use it as a slug is not a bad thing to know, and in a survival situation could mean the difference between life and death. However, it is something that the firearm was NOT designed to do and you are taking a chance every time you do it. Same with steel shot through a full choke. Many shotgun owners shoot steel through full chokes for a while and nothing happens, then one day BOOM. The point is that there is no reason under normal circumstances to put yourself in danger for no real reason. That's what slugs are made for.