X-ray, or Magnaflux ?

[John Mazza]

Does anyone know of a person who x-rays or Magnafluxes shotgun barrels ?

I want to get a definitive result on what looks like a crack (or localized pitting) inside my twist steel 12 gauge barrel.

Thanks !

[Dave Suponski]

John, This has been dicussed here and on other forums as well. Because composite barrels are a myraid of welds (for lack of a better term) I don't know that x-ray and magnaflux would give you a true picture of a fault on a weld line.

[John Mazza]

In theory: Even a mass of good welds should still be able to be x-rayed. Each weld should be solid metal, so any gaps, voids, cracks, inclusions of a differing density, etc. should show up as a defect. (Again, this is in theory...)

So, again in theory, a properly "welded" set of twist or damascus barrels should be one uniform solid tube (conprised of iron & steel - but still a uniform solid piece of metal).

...but after 125 years...who knows ? Heck, I can "feel" a slightly "ribbed" texture to my barrels. My guess is corrosive agents (sweat from hands, elements, BP residue, etc.) have selectively etched the barrel surface. Could the same thing have occurred inside too ? Not to mention, how would one even x-ray a barrel anyway ? I've seen metal plates x-rayed, and you have the radioactive souce on one side of the plate, and a film on the other side. Source penetrates one metal surface & "exposes" the film. Unless you could get the source inside the barrel, you would need to send the x-rays through both sides (diametreically opposite each other) of the barrel to expose the film on the other side. I can't imagine that turning out too well.

...and Magnaflux - would that illustrate every deep scratch in the barrels ?


I'll probably just not shoot it...

[Dave Suponski]

John, I think Magna flux would be the better of the two options. We used to have a company here in town called Metal-Test where I used to bring my race motor parts..Cranks ,rods,rod bolts etc.for Magna Flux testing. I don't know if they are still in business. I have an old set of twist barrels here. I wonder if it would be worth the money to have them test them and see what they can see. The results may prove interesting....

[John Mazza]

Agreed. We used to have a company Magnaflux our crane hooks years ago. Now, everything's dye-penetrant testing...

[Dave Suponski]

I just may have to look into this John. Could make an interesting Parker Pages article....:rolleyes:

[Ed Blake]

When in doubt, don't shoot it. Sounds like those barrels have gotten inside your head.

[John Mazza]

They have ! (I guess I can always just shoot the right barrel - trap shooting.)

[Dave Suponski]

A few years ago I had a 10 gauge NH here for the 3 day inspection after going over the barrels with a loupe I found an area that just didn't look right. It was either a deep scratch or a fissure. Couldn't get past it...just sent it back...

[John Mazza]

Linear defects (cracks, deep scratches, etc) scare me far more than pits. {I have a drilling with freakin' ugly pitted bores, but nothing resembling a crack. I shoot it often with RST's lowest pressure shells.}

[Dave Suponski]

Agreed John

[John Liles]

Just a thought here guys, but over the years in the bridge building business I've had need to check welds in some pretty precarious places, usually in existing structures that had for some reason become suspect.. In many of those places, positioning a "source" for traditional X-ray examination wasn't feasible or sometimes even possible. In those instances, we've utilized ultrasonic testing. Owners are sometimes hesitant, because a permanent record (X-ray film) is not produced by the process. The process ends when the machine is turned off, but a qualified technician then reports to the owner what they've witnessed during the testing, and that usually will suffice when X-ray testing isn't possible.
In the current context, where defect discovery is primarily for piece of mind of a buyer or potential shooter of a composite barreled gun, seems to me that U.T. might just be the ticket. Transducer configurations vary, and none of the standard ones will accommodate a shotgun barrel with any purpose built precision, but even a perpendicular transducer would work for a specific spot that someone had reservations about.
I'm sure Francis could weigh in here with additional thoughts, and more than likely I've wasted everyone's time with these ramblings, but as stated before I've seen U.T. display weld and even base metal faults where more traditional NDT methods were impractical or impossible.
Food for thought,
John

[Dave Suponski]

Thanks John, It's all good input.

[Phillip Carr]

I would possibly try Fluorescent Penetrant Inspection. We use this and a skilled inspector can detect even very small defects very accurately. Many aircraft service centers have the ability to do this. I am sure there are other industries as well. Fluorescent is dye penetrant inspection but uses a fluorescent penetrant and a black light to detect cracks. I cannot tell you how this would work on Damascus barrels but in theory it should provide some good results.

Phil

[Linn Matthews]

We used to use the fluorescent penetrant for inspecting large graphite blocks. You spray on the penetrant, wait, wipe and then put a "black light" on it. The penetrant collects in the cracks and fluoresces under the light. It worked well