Hey griswold, slug guns and muzzle loaders are all that I use. You should always start out at 25 yds. Once you have the gun zeroed at 25 yds., move out to 50yds. Get conffident at 50 yds. ,then moveout. Slus are heavy and move slower than a rifle bullet, so there is more drop. Depending on the brand , there could be as much as 9" drop. Try several brands to see which one groups the best for your gun. Tony