More on vintage spread-shot pellets

[DrGunn]

I also suspect the rifling will have some affect on the patterns you are getting. I have read elsewhere (for example see here: https://www.theboxotruth.com/threads...un-barrel.377/) that shot fired through a rifled barrel results in a large spread and a “doughnut pattern”.
In this case I would hypothesise that the chalk sticks don’t engage the rifling that well and so don’t spin that much. The tight fitting wad is more likely to engage the rifling and impart spin to the mass of shot, throwing it outwards. I think it would be very interesting to repeat these tests with a smooth bore barrel and compare the results.

[keith66]

^^^ This is true, Gough Thomas experimented with this many years ago & there is an article in one of his books on the subject, He was talking spreader cartridges for shotguns of mainly 12 bore & the same effect was noted. Rifled chokes opened the shot cloud markedly. Obviously such items would need an fac today.
As Jerry cornelius points out a Giffard shotgun may work quite well with these. But from experience with a 9mm rimfire shotgun you are never going to get good patterns from shot clouds this small. The 9mm rimfire is good for about 8 yards max, 10 yards is stretching it. The driving wad disturbs the pattern centre so much that by that distance the pattern is like a donut.