I will be sending my primary in June and was wondering when to send letters of rec? Should I send them out shortly after the primary or wait until the secondaries arrive? Thanks

I would probably wait until you get the secondaries. There are a couple of schools (Michigan State comes to mind) that require your recommenders to use their forms. And if you get your primary sent in by June/July, you will get your secondaries by early August which is plenty early for your recommendation letters. Just make sure you have contacted the people early enough so that they can have something planned for you. Good luck!