That measurement should around be 9" from the muzzle. If all other measurements show the gun is still in proof, there is no major pitting or bore problems, etc. I would personally not hesitate to use the gun. You need to have a qualified SxS smith give the barrels and action a good going over. If the smith in mention doesn't understand proof marks, doesn't use a bore mic, or doesn't have a wall thickness gauge, your in the wrong shop for this type of thing. Also don't expect him to grade it "safe" or "unsafe" to shoot. Most guys wouldn't tell you that about a modern gun, much less something one hundred years old, damascus or fluid steel for that matter. Expect more of a statement of the facts, the gun is still in proof, wall thickness is as stated, metal shows no dents or pitting, the action is in good working order. Things like that. .022" wall near the muzzle end of the gun doesn't worry me, as long as everything else is kosher. Ultimately, the decision will be yours. Just remember that the guns of that period were built to handle nitro loads with pressures of around 7,000 psi and shoot it with loads appropriate to that period.
You're probably right, this may start a small maelstrom of differing opinions, but most here are better educated on these matters than the average, so it shouldn't get too bad.
Luck,
Jim
Last edited by JimfromTrafalgar; 04/01/11 11:49 AM.