Fingers crossed folks that you can see these pictures, (my first posted on a forum without help). This is a Rouxverschluss, a snap-lock, under-lever Drilling that was made near Suhl (Z and M are intertwined on bottom of rifle barrel so it was made in town of Zella Mehlis). It's marked on the top rib "W. Müchler Söhne, Neuenrade n/W". (Germany). It may have been made in either 1911 or 1916.
It was purchased, in a vey poor state of care, the gun shop rang me because they knew I'd get it working again, (we're getting there!). The firing pin springs were rusted out, some broken and there were no two the same. These have since been professionally replaced but, because they are so close together, they clash against each other on discharge. This robs them of their energy and they fail to strike the primer with sufficient energy. Clearly something is wrong. Perhaps the original springs were square in section and so did not interfere with each other when released. Any suggestions gratefully received if you have seen this problem and the solution to it before.
http://i1256.photobucket.com/albums/ii489/ten_gauge/DSCN8921.jpghttp://i1256.photobucket.com/albums/ii489/ten_gauge/Rouxverschluss.jpghttp://i1256.photobucket.com/albums/ii489/ten_gauge/rouxverschlusskiwiIMG_1223.jpg 
