Those of you recommending the use of steel shot and slugs through full chokes please site the ammunition company that recommends this.
I have not seen any recommendations either for or against using slugs in a full choke bbl from the ammunition companies. I am not a regular user of slugs, bought a few years ago for my wife to go on a "Diana" deer hunt on a local management area which had a shotgun only (slugs, no buckshot) restriction. She killed her deer using the left, full choked bbl of a 20ga double. It did not hurt the choke. I know a good number of locals who regularly hunted this area with full choke guns with no problems. My Father-in Law lived in Southern Illinois which allowed deer hunting with shoutgun slugs only. He regularly killed his deer with a 12ga model 58 Remington SA withth a 30" Full choke 3" Magnum bbl which he used for everything he hunted. Both of these areas currently allow use of muzzle loading rifles, but even this has not always been so. I do not know about some of the more modern slugs, but do know that both the Foster & Brenneke slugs would go through a full choke quite readily without any damage to the bbl. The solid portion of the Foster was small enough to pass through the choke, the hollow skirt would expand from the pressure, but squeeze back down in passing the choke. The Brenneke had fins which gave a fit to the bore but could also squeeze down through the choke. Millions of these types have been fired through full choke guns over the years with no problems. A solid round ball is also suitable as long as its diameter is small enough to pass through the choke. I learned all this many years ago. There are today a number of speciality slug makers & what you say may be true for some of these, but it is certainly not an across the board thing for all types of slugs.
I did not recommend Steel Shot only stated the caveat against slug use was definitely not all inclusive.