I'll get an email for Mark and ask. But Diggory was clear that the date of the Lang's was on the bill of sale....
And Daryl, I'll let Steve comment more but my $.02:
-- I don't believe Birmingham began making barrels with lumps or center-break pin-fire actions until about 1861. They couldn't have made those guns.
-- As for importing barrels and actions from Belgium, that's always been a possibility. Trantor was doing that for revolvers in the mid-1850's. But my understanding is that imported barrels have to be stamped in a particular way. I don't know about actions but until a Belgian connection can be proved, would prefer to put the credit for making these early guns on London craftsmen - and that appears to be who Blanch was talking about when he wrote about the change over from breech plugs to lumps, etc. and the lessons his men had to unlearn and learn.
