helllo, new here and saw your thread and wanted to reply since I have been doing a ton of slug shooting lately.... dont mind the trash, just before monthly clean up
this is a short video of a 200 yard shots on a rangefinder , 12" gong. 20" smooth bore with 12ga Centurion 1 1/8 oz rifled slug 1400 fps.
I was holding about 2 - 2 1/2 feet high. I hit it several times but couldn’t do it every time
I haven’t tried but I think with a rifled barrel, a sabot slug and scope I could hit it more times than not
As far as penetration, I made the stand with a pressure treated 4x4 on top. I dug a couple out and they only went in about an inch.