Bulzeye, it woul make on sense to shoot a rifled slug in a barrel with rifling and the grooves already on the rifling would most likely clash with the rifled barrel giving you poor accuracy. Rifled barrels were made for saboted slugs, the slugs are smaller than the barrel bore and the plastic sabot takes the rifling causing the slug to spin giving accuracy. don't try to skimp on your ammo, it is what does the job for you.