Recently acquired this 10 bore Holland and Holland Double Rifle finished and sold in 1882

3 1/4" case, 26" Damascus barrels, 14lbs 8oz, barrels weigh a stout 7lbs 4oz
Fully rifled, 9 groove rifling with ~1-85 twist proof stamped 11 and groove-groove is ~.780
Non rebounding locks, so one MUST bring the hammers to 1/2 cock before opening the breech.

I have brass 10 bore cases and a proper ball mould from Tanner Ball Moulds, UK so I should have it shooting soon.

EDIT: added more pictures
- Mike