When I was in my teens I was possum trapping in the bush in New Zealand. I got the bright idea that a cheap single barrel 12 gauge with an 18" barrel would be just right to carry slung over my back to nab the odd deer or pig that one runs across every now and then. It was cheap enough to carry in all kinds of weather (it was usually raining) and light at 5 1/2 lbs.

I loaded ammo using Dad's shotshell reloader and just pouring out the shot and replacing it with a ball that was a good fit in the barrel inside the shot wad. It star crimped sort of OK. I have no idea what the load was. Amazingly, it shot fist sized groups at 50 yards and I can tell you the ball would rake a pig from one end to the other.

It was quite a handful though...