When playing a D&D variant, clone, or simulacrum, that has allowances for fighters making multiple attacks against multiple 1 HD and/or less opponents; and are playing in a campaign where guns are somewhat 'normal-ish'; and the fighter is using an automatic, semi-automatic, or bolt, lever, pump action or equivalent firearm or energy weapon; and the fighter is not currently engaged in melee; allow the fighter to use their multiple attacks against multiple 1 HD and/or less foes with missile attacks with the aforementioned gun, limited by the ammunition capacity of said gun.
I'd probably let a high level fighter with a good dexterity score use two pistols with this houserule.
