Jeff G.:
I can only make a stab at it and it looks like some sort of hybrid. It's set-up like a O/U triggerplate action but the hammers and V springs are on the frame. Very interesting and nice effort. Any additional markings or stamps on the frame or triggerplate? It has a Kersten bolt but is there any additional underlug(Purdey type) lockup? I'd assume that underlever trips something else?

Kind Regards,

Raimey
rse