Vegard - 12 bore is 12 gauge, 16 bore is 16 gauge, etc.

You will probably have to use a .640" round ball due to the chokes. I would then use a patched round ball as explained in the private message - or - buy some plastic wads or plastic gas-check wads that have a cup on the bottom of the wad. Mind you, you cannot put plastic right on black powder without protecting the plastic from it's flames upon ignition. You will also need 1/8" hard card wads, called overpowder wads.

You load the powder, then the hard card wad, then the cupped wad or cut-off cupped wad with the cup facing up to hold the ball in the middle of the bore, then either fold crimp with plastic hullslike you would when loading shot or if you want to roll crimp, a disk of paper called a "B" wad or "BB" is placed over the ball then the hull is roll crimped with a special tool held in a drill press. You adjust the ball's height in the case with more or less wads.

You 'must' have some method of holding the ball in the middle of the bore as it accellerates up the barrel. I have found the gas-check cups cut off expended trap wads alying allover the ground at the loca trap range work well in 12 gauge round ball loads. Other guys here have had good luck with fibre wads with the centre cut out to hold the ball in the centre of the bore. This is important so that the ball is delivered straight towards the target without bouncing back and forth up the barrel on it's way out, then starting of at an angle at the muzzle due to being smaller than the bore. That was the problem with the old Punkin Ball factory round ball loads of the 1950's. The balls were were very much undersized and did not have anything to stop them from bouncing back and forth up the tube, coating the bore with lead and producing miserable accuracy past 20 yards.

With some work, and some good shooting, you should be able to make a diagram, with 2 sights (rear and front)of 5 shots into 3 1/2", maybe even better than that.

The maximum range is dependent on the accuracy you can achieve, range is not restricted by the power.

A 16 gauge hull will hold up to about 5 to 6 drams of real black powder, which will give a 440gr. round ball some 1,600fps. If you use 'Swiss' 1 1/2 powder, that velocity might be even higher. Of course, lighter charges can be used as well. I'd not hung with less than about 3 drams which is 82gr.

If you want to use it in Africa, you'll be more interested in full cases of black powder to get all the power you can. It would be very effective for most game, within it's accuracy range.

Keep in touch.