Re: Brass head question
If you are talking about the SST Slugs, the crimp is called a roll crimp. If you want to reload shotshells, a folded crimp is best (either 6 or 8). Slugs, that requires a roll crimp. Do a google on Precision Reloading or Ballistic Products. They both have roll crimp tools.
You cannot (or at least without a lot of difficulty) change a roll crimp to a fold (star) crimp.
Also, shotgun shells are more sensitive to component changes. If you don't follow a recipe from a reputable source you could have a ka-boom!