Three years ago I worked with a bullet maker on solid copper saboted slugs of 436.5 grs HP variety. We ran the developed components thru a Remington 870 using a smooth bore barrel and a rifled barrel. We also had a Leathwood shotgun scope mounted on each barrel. As far as The Box of Crap testimony, we didn't find the accuracy to be bad at all. It all depends on the firearm, the condition of the firearm, shooters ability to absorb 12 ga ammo from a benchrest,and the expectations. If a 2.5" group at 100 yds is your idea of accuracy, that's what we got out of it with both barrels. That was much better than I ever thought a shotgun could be.The major difference was in the velocity. There was also a major difference in felt recoil. If I were to use a saboted slug for my personal use, I would run it out of a rifled barrel. But if all you have is a smooth bore, the only area you have any concern for is penetration on hard animals like a big hog. A shoulder shot will most likely go thru the shield but it's not going to deform the bullet enough for a much larger wound channel and there won't be a pass thru.
If you just want to try them in your shotgun, Remington loads a saboted solid but around here they run about $2.50 a pop.