No, not the Brady Bunch. Zombies.
James Rummel has some tips on the proper weaponry for battling the undead hordes.
He was inspired to write the post after reading World War Z: An Oral History of the Zombie War by Max Brooks.
If you’re interested in such things, it’s a good read. I read it this past summer. The military had to give up most of its wiz-bang gadgetry and go back to semiautomatic rifles to effectively fight the zombies. Stuck with 5.56, though, because it was readily available.