As long as you have a concealed carry permit, the sky's the limit.
Not necessarily. In my former digs of Memphis, Tennessee, our Handgun carry permits most certainly did NOT allow the carry of a loaded longgun, shotgun or rifle, within the confines of one's vehicle.
To get an approximation of the GI carbines that I've carried in most of the personal vehicles I've owned since high school, I had to go to a shoulder-stocked C96 *broomhandle* Mauser...with a 20-round magazine, and several reloads of interesting ammo available.
Happily, that's not a consideration for me in my present locale, though potential distances hereabouts suggest a Garand or FAL as a better choice yet. But maybe I'll add a carbine anyway, just for old times place and to make up for the time lost while I was in the Dark Kingdom of Mordor. And the Tennessee Firearms Association is working to include longguns as suitable for carry by licensed persons.