The spin doctor is the perfect tool to recondition stubborn or damaged shotgun hulls. Many shotshell reloaders know that some hulls have a very strong ";memory"; and will maintain only a partly opened crimp after firing - creating problems for reloading. When used with an electric drill, the Spin Doctor gently reconditions stubborn or damaged shotgun hulls with heat created by friction. To eliminate hull-mouth problems, start fresh by conditioning all your hulls.