What is the difference and which should I use to reload .38 special for my S&W revolver? I have never reloaded pistol bullets before, just rifle, so any tips would be appreciated. miles
Taper crimp dies are for autoloaders, roll crimp dies are for revolvers (and other guns where bullets jumping forward or being pushed backwards is inadvisable).
The Lee handgun factory crimp die offers either a taper crimp for autoloaders or a roll crimp for revolvers. The item that particularly sets them apart from other crimp dies is the addition of a carbide sizing ring.
http://leeprecision.com/xcart/Lee-Carbide-Factory-Crimp-Die/ 
