Hi, I've got a late 1920s kersten action o/u shotgun that I just bought (miller val greiss). There is a through pin in the lower right corner of the frame but no cocking indicators. The gun was sold under the miller val greiss name, but I thought a lot of their stuff was made by one or the other merkels.
The firing pin from the lower barrel only makes a slight ding on the primer and it won't fire. I tested it on two brands of shells. From looking at the action without the barrels it appears that lower firing pin does protude a little less than the upper, but not by too much.
Any ideas or suggestions? thanks