Thanks, guys.
PGR, from a couple of reviews, that shotgun sounds like an unreliable, poorly manufactured POS. I wonder if a24 went a-Googling for jargon, found that thing, and didn't read any user reviews.
BD, sounds like the sort of shotgun one might use for close-quarters self-defense - wide pattern that hits many would-be attackers, probably none fatlly, but injuring sufficiently to give the one attacked the upper hand. But usability in such a situation is critical: a well-made double-barrel is heavy; after two shots it's reloading time (not fast, even if shells are close at hand). A 5-shot or 7-shot pump-action shotgun with the appropriate barrel length and choke would seem a better choice.
I think a former Marine would know such things (a lot better than I do!) and have chosen a better home protection weapon.