This is a total and complete crock!! IF you use lead bullets, your barrel will last literally forever. If you shoot cloth patched or paper-patched balls/bullets, it is the PATCH MATERIAL that wears out the bore, NOT the powder. I don't know what damage a plastic sabot causes,but the mechanism which wears out a ML barrel is entirely different from what ruins smokeless powder barrels. In smokeless powder arms, the hot powder gasses actually melt and carry away a small bit of the barrel steel each shot, just like a cutting torch. BP operates at so much lower temp/pressure than smokeles that this does not occur. Instead, the barrel is actually worn away by the friction of the projectile. Leadbullets are too soft to wear away steel, but paper and cloth patch material does!