...buy something you could carry conformably because you would actually have with you when the need arises....
I'll restate this. Buy something you
will carry. Bigger magnums might give you a warm fuzzy but are useless when left in the truck or the cabinet.
I'd also offer cautionary advice... It's your choice to carry a secondary firearm (handgun) and I don't dispute it. That said, be wary of the sense of security/boldness it might provide. Most of the scenarios listed ended without shots fired and without physical confrontation. Although the people were scared (rightfully so, always maintain a healthy respect for danger even when armed... especially when armed), they all survived without a fight.
I'm not opposed to packing heat, but the right mindset is always essential.
