I'll have to respectfully disagree with you about said belly bands.
When worn, for a man, right-handed, as though in the appendix position, but opposite it, in a belly band, with the grip to the midline of the abdomen, and with the last two buttons above the belt line, sewn into the button hole, and the shirt then affixed with velcro, access is as simple as plunging your hand thru the shirt front opening to grasp the weapon!
If the weapon has an exposed hammer, place the thumb of the weapon-hand over the hammer to prevent its snagging on the shirt front.