I cant speak for Lyman sabot slugs in a smoothbore. They can be used in a smoothbore, but I have serious doubts about stabilization. The best barrel for Lyman sabot slug is a rifled bore. You could try 69 caliber round balls in a smoothbore -- I have heard they are devastating on anything they hit (ie, about 500 grains of lead). BPI has a technical brochure on RB slugs. I can scan it and send to you via email. For a smoothbore, I suggest a RB over the Lyman sabot slug -- molds are cheaper, too. The .69 caliber RB mold from Lee is about $25.00 shipped. My preferred bacon bomb alloy is three pounds of wheelweights to 4 ounces of linotype (added tin for flow,antimony for hardness), water-quenched.
The hardest hit pig from my allow and slugs went nine feet, and that was only because the slug knocked him into the brush while blowing out the offside shoulder. The RB slug should yield even more devastating results.
ST762