I have heard the term used and am familiar with what it means. My question is, how does one know if the double is off face? I presume that with standard rounds (no excessive pressure), one can shoot literally hundreds if not thousands of rounds before there is any risk that the barrels come off the face. I know with mine, my shoulder will give out well before that is a problem. But I am still curious how one knows whether the barrels are off face, is it obvious? What do you look for? And once it happens, how is it fixed?

Mike -

There is probably a more “measurable†means of determining if a gun is “off faceâ€, but at a gun show or in a gun shop this simple method will satisfy your curiosity.

Remove the forend iron, hold the lever in its open-most position and while grasping the grip with one hand, try to laterally move the barrels back and forth with the other hand.

Don't let the barrels swing "open"... hold them "closed", i.e.: held up to the face of the receiver.

“Off Face†means that a combination of wear between the barrel hook and hinge pin have developed a tolerance that no longer holds the barrel breach against the face of the action when the gun is closed. Once the tolerance develops, it is only exacerbated with continued firing as the two parts (hook and pin) will wear much more rapidly.

There are a few solutions, depending on the gun.

If the frame has a removable hinge-pin, typically it is removed and replaced with one larger in diameter to compensate for the wear on the hook. This is the simplest and arguably the best solution for this type of config. because it requires no welding to or additional machining of the hook.

If the frame does not have a removable hinge-pin, then a section of the hook is removed (the portion that contacts the hinge-pin) and a piece of steel is machined and usually dove-tail fitted to the front of the hook to take up the tolerance.

The preferred option for a non-removable hinge-pin gun is to tig weld the hook and machine it back to fit the hinge-pin.

IMO - I’d guess that more guns come “off face†from improper care of those two mating surfaces (the hook and hinge pin): usually from lack of lubrication. It is metal wearing against metal every time you open the gun and it should be protected with a good grease. The grease should also be removed and replaced regularly to keep grit from getting into the grease and accelerating any wear.

Firing the gun no doubt has some measurable wear on the two surfaces, but I’d say that shooting the gun probably doesn’t have as much impact on wear as improper lubrication.

Short chambered shotguns (2&1/2â€, 2&5/8†etc…) are known to come off face because someone shot 2&3/4†shells in them for an extended period of time.

Keep your hinge-pin and hook cleaned and greased and you shouldn’t have a problem in your lifetime with your gun coming off face. If you do, a few hundred bucks is all that is required to set it back.

In some extreme cases I guess, the frame could be sprung or stretched, but that's another subject.

Mike:

What you're looking for is detectable play between the barrels and the breech face, with the fore-end removed and no locking lugs engaged. In other words, remove the fore-end, turn the gun upside down, and push the top lever to the right, then wiggle.

It's fixed relatively easily. A new hinge pin is made for those guns with removable pins. With fixed pin guns, the hook is tigged up and refit. It isn't a big deal. However, you've right, a good quality double should stay on face until the bores are shot out, so when they don't, it means they're being abused. Inadequate lubrication will do it, but excessive loads will do it faster.

Never let some hack hack up the hook of your gun with a dovetail. There is no need to do it that way anymore.
------------------------------------------------
"Serious rifles have two barrels, everything else just burns gunpowder."