Yeeeehhhaaaaaaaaa!!!
Finally got down the range and straight on the firing point!!!
Chambers reamed from 0.373 out to 0.379, new ball mould at 0.380.
24grns of holy black, ball and a smear of secret formula greasy stuff,
1st pistol, 5 shots, slow fire, two handed at 20 yards,,,,,,,2.5" group
2nd pistol---ditto---------ditto----------ditto-------ditto----,,,,,,,,3.25" group
This was immensely satisfying from a pair of pistols that would barely print a 12" group before being reamed.
So my advice, for what it is worth, if you have chambers that are smaller than the barrel groove diameter is, ,,,,,wait for it!!!
Get them reamed, the cost is well worth the small expense of engineering and new mould.
Your (highly delighted) pard, UKshooter.