I burned up probably $300 worth of slugs over 10 years ago. Link to my post a about it here:
https://www.24hourcampfire.com/ubbthreads/ubbthreads.php/topics/360390/Re:_Slug_guns_and_accuracy#Post360390

Gist of it was, my gun LOVES the now dicontinued Remington Buckhammers. Fortunately, I secured a lifetime supply. 2nd best were Remington Copper Solids at 3.5" 100 yards.