Some work ok. A lot depends on the exact diameter of the slug and barrel. Slugs have a longer bearing surface and friction in the barrel than a pellet. Slug too big, or barrel too small, and you get slowing from too much friction. Slug too small or barrel too big, and you lose velocity from blow by.
@donc tried with my 56th and it was terrible. Went from dime size with crossman premier to about 2.5 inch at 25 yards. A nice man from another site sent me some to try on my Diana. He casts them himself and wanted to know how they would shoot out of a springer. I want to say they was around 25 grain. It's been awhile but I just remembered they didn't shoot well at all. They may out of something else but my Diana just hated them. Maybe it was the drag in the barrel with drop in fps.. I don't know, I just shoot the breeze and nothing scientific
