The amount of force needed to start an ordinary projectile down bore is often more than sufficient to cause deformation and ruin its ballistic qualities. Black Belt Bullets are one-thousandth of an inch underbore and the Power Check is slightly overbore.
Muzzleloading and Blackpowder Cartridge Firearms, Kits, Components, Ammunition and Accessories for the Builder, Hunter, Shooter, Re-enactor and Collector.