How about one gun, two different ammo loads? A heavy hollow point for sentry, and a hot jacketed round for combat.
...which brings me to another topic - I think we should consider expanding ammunition for military pistols. The U.S. isn’t a signatory to the first Hague Convention that prohibited it for reasons that seemed sound a century ago but are now a little questionable. The second Hague Convention, which the U.S. did sign, doesn’t prohibit it IIRC. Anyone who knows more about that, I’d be delighted to learn.