I think you have it pretty much straight, with an ounce of #6 shot it will be reliable on squirrels out to a maximum of 25 yards, maybe a bit less. A small bore rifle would take the same game at the same or longer range while using half the powder and 1/4 the lead. They were built to comply with certain game regulations and if you're not limited by law to a smoothbore there is no reason to use one., which is why T/C stopped making them.