The following is by my own definitions of the matter of off the face and loose actions.
If i say an action is tight i mean to able to close the gun normally and feel that the bolts are securely engaged in the bite thereby holding the barrels firmly closed.
On very worn old guns you can sometimes feel or in worst cases see that the the forend is loose on the bearing which makes the gun feel sloppy and flop open.
Sometimes the bite or bolts are so badly worn there is some up and down movement in the barrels when closed normally.
By my definition either of these two situations describes a gun with a loose action.
A gun either has a tight action or a loose action, there is no middle ground, or allowance made for the age of any particular gun.
I have a gun going left of center and i will get it tightened, though the gun is not obviously loose, the left of center is a good indication of the gun wearing in and constitutes normal wear for an gun that's been shot.
I have tightened loose guns before and in the case i refer to it required the barrels to be put back on face from wear on the pin, the hook had to be welded, once this was done this bought the for end back onto bearing on the knuckles, then we had to tighten the bite, combination of this work took a lot of time but ended up with a gun that opens easily without play between the knuckles and forend, closes securely with the barrels on face, and the action tight.
I gun may be tight and on the face or tight and off the face by my definition.
A gun that is off the face by my definition is a gun that's barrels are no longer making any kind of contact with the breech face.
A gun that is tight and off the face my feel like a perfectly find gun however if shot wear will quickly turn the gun loose.
A gun that is loose and off the face will feel awefull, the forend may move against the knuckle, the barrels will drop open heavily and jar closed then the locking mechanism will hold the gun closed but there will be play in the mechanism.
I think the best way to judge is by feel,
