Granger:
The 'bar' of an action is the section that lies under the barrels with holes for the barrel lumps and the hinge pin at the front.
The 'bar' of a lock plate is the part of the lock plate that lies along the side of, and is inlet into, the 'bar' of the action.
The pin I mention is the locating pin on the main spring which, in a bar-action lock, is usually visible towards the front end of the 'bar' of the lock plate.
In a back-action, this pin is usually towards the upper tail of the lock plate but since it is usually indistinguishable from other pins such as the interceptor sear spring pin, this information is not terribly useful!
