As others have said, Most of your calibers will need a small pistol primer. Federal Champion and a few others in .45 acp take a small primer as well. Winchester White Box use large pistol primers as do the majority of other .45 brass. You do need to check your brass closely if you are using once fired brass in .45. I load mostly for range use and not competition shooting. I use the same load in .45 when using either type of primer. I also have one press set up just for .45 large primer. The other press is just for small primer calibers. It makes things easier for me. It also saves me a few minutes time. Often when I'm loading .45 ammo, I have both presses set up for .45 and can get all my brass done before switching to something else. I do need to shoot up some of what I have loaded in the near future to have some more brass to load.