Magnum small pistol primer and 9mm...
Perfectly acceptable in my opinion provided you are properly working up loads.
Personally i have been using srp in place of spp with no problemo. If you are not comfortable in your skills and knowledge of reloading DON'T try it.
I only haven't purchased magnum primers because I haven't had the need, but I would do it in a hot second if that's all I had available.
Work up your load