If I owned a M4 or AR type rifle for home protection, I'd have it; "cruiser ready": empty chamber, safety(ambi) on, 10/15 round rifle mag(PMAG or the cool type that shows the remaining magazine rounds: red/yellow/green
Unless I expected armed threats or death threats, a limited AR magazine would be okay. I might keep a loaded Cmag or Beta rifle magazine close by,
Unlike Hollywood, you are HIGHLY unlikely going to get into a major shootout. 2/3 rounds may be expended total in a home protection event.