Some days ago I tried a method that Daryl explains a couple of times.
That is a paper cone with powder and a round ball.
I used only paper and balls and it works fine shooting at 50 meters (55 yds.).
It was very easy to load first one and second a little harder. I swab the bore and load the third charge. Then multiply it by 2 as it is my Kodiak double rifle. LOL
As you can see on the target (well you cannot see it), first shot, right barrel was out, down and to the left. You can see left barrel bullet as “1”. The recoil and sound of the right barrel was unusual and light, I think I tear the paper when I load.
Second pair was OK (“2”) and, as it was a little difficult to load I swab the barrels and load for a third time, you can see those as “3”.
Accuracy was the usual for me and the rifle as I shot without a rest.

I thought you would be interested in this test.
It looks promising but I have no RB left I will cast some and try again.

Thanks
Martin