From Offcial Site:

DO NOT USE SHOTSHELLS IN FIREARMS WITH PORTED BARRELS OR PORTED RECOIL COMPENSATORS. DO NOT RELOAD THESE CARTRIDGE CASES. These cases are marked NR (Not Reloadable). Rupture of reloaded cases can cause severe injury. Intended for short-range pest control; not recommended for self-defense. Cylinder lock up may occur in lightweight revolvers due to capsule movement resulting from recoil inertia.
May not function properly in rifles.

Product Overview

Snakes and other pests are small targets and leave little margin for error. Take them out with our exclusive centerfire handgun shotshells. The loads produce consistent patterns that make it easier to knock down nasty critters in tight quarters.