My dad gave me a few of these and I told him they can't be fired in a smooth bore with any accuracy. He keeps them as just in case slugs when he is in the bush. I contacted hevi shot, and they said they are fine in a smooth bore shotgun. I am very interested to see how they match up against challengers. It is hard to find good shotgun slugs in Canada. At $5 a slug, they better be good. has anybody tried these?