Pick any action, any caliber (except the very new ones) and it's been sucessfully used as a defensive gun.
In our colonial and frontier days, the most common firearm was a single-shot smooth-bore, first muskets, then shotguns. Then single shot rifles, frontstuffers, then self-contained metallic cartridge.
Lever actions (which he thinks are worthless) are the original assault rifle, and are still able to be used in that capacity.
So, really, there is no such thing as a non-defensive gun, only a narrow mindset.