Isn't it just a Henry Jones under lever/screw grip Gun?, pretty common , n very stout,so I hear.I have a nice Greener Hammer pigeon with the Jones action..I really like the way you can feel that lever really grind down & lock those bbls right down n solid..though it is a little slow with all the movements to unlock n lock again, but I find it very mechanically satisfying ,looks lovely mate
franc