doublegunshop.com - home Forums General Discussion DIY Gunsmithing @ doublegunshop.com Chamber erosion- when is too much really too much?

I'm checking over a Damascus barrel set for a friend. There is considerable erosion just ahead of the forcing cone in the right barrel. The pics tell the story:





Lengthening the forcing cone could take care of this. The chamber is already 3" deep and not knowing the actual depth of the damage concerns me. Is it really worthy of consideration? Where does one draw the line?

The moon crater look and already chambered out to 3" would have me leave it alone.
Of course wall thickness in the concerned area can be measured and then the whole thing evaluated again about lengthening the forcing cones.
But the overall condition at first glance all the way down the line from the pics provided just doesn't provide me with a lot of promise for safely reclaiming.
JMO of course judging by what I can see.

How does removing more metal make it better other than making it easier to keep clean? And 3" sounds like it has already been cleaned up once. Any idea about the metal thickness at this area. Rule number one to me on doubles with suspect barrels in general and chamber in particular is that if they are suspect that are not to be shot until proven safe. Eyes, noses, hands and fingers are not trivial things to put at risk. The world is full of other safe guns.

Kutter, Jon thanks for the feedback. Your comments make good sense. The wall thickness of the area having the crater is 0.136" which allows some room to work. But, looking at both barrels again using different lighting revealed another issue that worries me even more:



From this pic it's easy to see corrosion following the twist weld seams consuming roughly 50% of the length of both barrels. The bores already measure 0.005" over standard, 0.032" wall thickness 12" up from the breech so additional work to clean things up is a bad idea. Beside that, who knows how much of each weld seam is eaten away by the corrosion? How deep does it go? This barrel set looks good on the outside but inside is a scary sight. These barrels are unsafe, attempting to reclaim them will serve only to make them even more dangerous IMO. So, guys this is where I draw the line. This old hammer gun has undoubtedly earned its retirement and deserves a peaceful rest hanging over a mantle.

Hank

Hank, I've never seen pitting and rust follow the welded seams as your photo indicates. I shoot a lot of damascus, not all pristine, so have quite a bit of experience with it. In this case I know I'd walk away from any effort to clean it up. Only possibility I see is to tube it to a smaller gauge, not a really desirable alternative given the cost and change in dynamics.

I have several shotguns with Damascus or twist barrels. All have some amount of pitting. But I have shot them with light black powder loads. I don't think I'd chance shooting the one you pictured. Unless it's a valuable gun worth relining the bores, I'd enjoy it as a wall hanger.

Joe, having worked with dozens of old barrel sets over the years this is a first for me too. If I offered a guess as to what allowed this condition to develop it would include neglect and quality of the forge welding but it would be just that; a guess. Lab analysis might uncover what happened but there's no need for that. This artifact is over a century old and simply has seen better days.

Bibbyman, as we all know you rarely find a Damascus barrel pit free. If you do chances are it has been back bored. I have built several double flints using barrels with moderately pitted bores that are perfectly safe and pattern well. As for value, my friends double has no real value other than sentimental. It has been in his family four generations and says he has the perfect place for it.

In summary, these barrels are dangerous and unsafe under any condition IMO. So, to remove all chance of mishap we'll plug the chambers and weld them shut. One may ask "Isn't that a bit much?" As Mark Twain once said "It's better to be careful 100 times than to get killed once".

Hank

Why wreck it worse. Maybe, take out the firing pins and separate them from the gun, or put them under the butt pad wrapped in a note saying the barrels are unsafe. If someone wants to fix it right, then give them the pins. If someone doesn't know what they're doing, they wouldn't likely know why it doesn't shoot or care to figure it out. Only thoughts is all, who would want a wall hanger with weld burns and splatter on it.

Craig, how will plugging and welding the chambers shut wreck it worse? Apparently my previous post lacked clarity. We're sealing the chambers shut, not welding the barrels to the frame if that's what you're thinking. Welding the barrels to the frame would wreck it worse and is a stupid thing to do. We're decommissioning the barrels, not the whole gun. Everything will still function as it should but the barrels will be made so they can never be fired again. Papers get lost, firing pins can be replaced but, obviously, a chamber plugged and welded shut can not be loaded. My apology for any confusion the previous post created.

Hank

Hank, it's my fault for coming across heavy handed. I figured welding would show as heat affect on the outside finish. I think that could end up with significant refinishing expense or an inexperienced hand giving it a try.

The firing pin comment was just a thought. We've seen here how difficult it is to stumble into pins that fit. I was just thinking that if someone takes the effort and expense have a new set made and fitted, they would easily be capable of assessing or getting help assessing the rest of the gun.

All I was thinking overall was that if I had a chance to hold my great grandfather's gun, I'd be trying to figure out if one of my grandsons could be a good keeper of it. Future generations are going to have to look things over and make decisions. If, and I have no idea, sleeving could fix this one, I would have it done in a heartbeat. I remember meeting one of my great grandfathers nearly fifty years ago only once when he was in his mid nineties. He was willing to chat, I was pretty young and didn't let it happen. I know his guns were long gone by then.

I really don't mind if you folks weld the chambers unusable, just explaining my thoughts.