If I recall correctly those "entry" slugs are LEO only, and are designed specifically to break down doors. Interestingly, those handy-dandy battering rams and other non-firearm entry tools can be purchased by anyone.
Regular slugs would probably do the job, albeit less efficiently. I think the purpose of the entry slugs is to speed along the job - to bust the door down as quickly as possible so the BG in the room doesn't have a chance to grab a gun or flush the drugs.