Identification and Value Family Heirloom

[Southpaw]

Originally Posted by Harry Collins

I'm not sure when paper shells arrived on the scene, but 12 gauge extruded brass shells used 11 gauge wads and thats about .750. I'm one of crazy ones that play Damascus and Twist Steel roulette. RST Shells make unequaled fodder for older guns. Their 2 1/2" loads of 1oz at a 1125 fps and 7/8oz at 1125 fps are a wonderful place to start. I shoot 10 and 12 gauge 1881 Parkers with Twist barrels with hand loads that keep the pressure at 7,000 psi and below. My 12 gauge Damascus Parkers are fed any 1oz factory load with velocities at 1180 fps and below. That said, Drew has a very valid point and his picture of the Parker who's chamber gave way proves it. Many old guns steel has crystallized and you can almost see it in Drews photo.

Harry

Good to see you kicking around with all your fingers.

A while back I posed a question about steel crystallization in these old guns and our resident metallurgist Edgar talked about it. I think I was refering to maybe fluid steel guns that can have thin barrels, but he put that thought to rest. Obvioulsy the forging process in these twist and damascus is different and there some instances of failures from innerstructure corrosion from years of early abuse and pitting.

[stumpstalker]

“Innerstructure corrosion”. As a layman I can’t imagine a more insidious-sounding barrel affliction.

If it does exist in a set of barrels, there seems currently to be no way to check for it.

Barrel thickness gauging would be irrelevant to determine its presence, extent or the frangibility of the metal affected.

“Shiny”; “pitted”; “bulged”, “dented” and “scuffed” are all observable, manifest descriptions of metal surfaces. Conversely, “innerstructure corrosion” is inherently latent.

Drew H. has said elsewhere on this Forum that: “No standards exist for radiography of pattern welded barrels, and x-rays can not differentiate between defects within the barrel wall, and pits on the interior surface”.

And further, “It has been my hope that a NDT expert with access to testing facilities, and doublegun interest, might develop a pattern welded barrel evaluation service. To my knowledge that has not yet occurred”.

Are there any recorded mishaps that with reasonable assurance can be attributed to “innerstructure corrosion”?

[Drew Hause]

Long answer, and the short version of "Zircon's" metallurgic study of the GH & VH barrels
https://docs.google.com/document/d/1...K7G9IBs4g/edit

Short answer

Welds can fail



Properly fabricated pattern welded barrels do NOT develop "orange lace"; "interlaminar elecrolytic [sic] corrosion" nor embrittlement (crystallization)

Freshly cut twist and crolle damascus barrels



Looooong answer
https://docs.google.com/document/d/1...hIiY62Hx4/edit

[Researcher]

With the wads available back at the time your family Parker Bros. was made, the recommendation for these guns was to use over-size wads -- 9-gauge wads in 10-gauge guns and 11-gauge wads in 12-gauge guns. Note the loads No. 56 and 57 for Parker Bros. guns in this 1886-7 Chamberlin Cartridge Co. catalog --
1886-7 page 6.jpg
1886-7 page 7.jpg

These old Parker Bros. guns with their over-size bores have been used for the last hundred and twenty years or so with regular wads. Over-bore barrels have been in and out of fashion throughout the history of cartridge shotguns. Today we have a number of trap shooters banging away with Stan Baker "Big-Bore" barrels with .800-inch bores all the way to the choke?!?

[edgarspencer]

Originally Posted by Russell E. Cleary

“Innerstructure corrosion”. As a layman I can’t imagine a more insidious-sounding barrel affliction.

Russ, do you mean 'Inter-granular Corrosion? This is a condition where attack takes place withing the grain boundaries. Generally associated with Austenitic stainlesses, and not unheard of in inadequately heat treated carbonsteel.
I can, as least conceptually, see where corrosive residue from primers and powder, will form acidic compounds given enough moisture. This would be much more serious in pattern welded barrels, less so in carbon steel barrels of reasonable metallurgy and sound heat treat practice.