Remove the “->GetClass()” part and just leave the variable name “testProjectileClass”. This should let the function know that you intend to spawn that class. You can find more information about this kind of setup from the following video.
Thanks for the response. I was having trouble because I thought that testProjectileClass points at object instance to clone (like unity prefabs), not at object class. Someone mentiond on the forums that it points at class, not instance, and that cleared things up.