If you change primers or any component you need to work up loads again. If a max load of 47gr of powder with Federal match primer is safe in your rifle the same load with CCI primer might not be etc,
Also some primers are better suited for military rifles with free floating firing pins like M14-M1- SKS etc. Certain brands have been known to slam fire on occasion.
For plinking with starting loads you could mix primers, but if you have that perfect .5 MOA 200yd load worked up and change primers it won't likely shoot as well.