They seem to be priced a lot higher than Winchester primers and are hard to find. Dale
If you email Alliant, they will tell you that you can substitute the Win primer for the Rem primer.One reason people buy them is because of the way Alliant expresses a bias in their loading data for listing Rem primers with Rem hulls, Federal primers with Federal Hull, and Win primers with Win hulls. If you are using an Alliant powder and a Rem hull, most of the recipes use Rem primers. Many are loath to substitute primers. And it's one reason I prefer Hodgdon powder, the data is more diverse.