"Mr Greener said this was defiantly one of their choke bore rifles, proof marks are from 1875-1887, he considers this to be a heavy (9 1/2 lbs) 10 bore made for round ball and brass cases."

In light of this, I maintain the chokes, which are usually very tight (deep rifling) compared to the bore, were almost bored out completely, - but - the muzzles appear to be too thin at the bottom of the grooves - that I do not understand.

The front sight block does look odd at well.