Thanks for reaching out Jason! There are two types of shotguns: those that have rifled bores, and those that have smooth bores. Rifled slugs are designed for smoothbore shotguns; sabot slugs are designed for rifled bore shotguns (it sounds unintuitive, I know, but that's just how it is). A rifled slug may damage a rifled bore shotgun. A sabot slug won't harm a smoothbore, but the accuracy would be absolutely atrocious! So long as your 12ga shotgun has a smooth bore, then this ammunition should function correctly in it.