Magnaflux for bore integrity?

[buccaneere]

Some ammo makers used highly corrosive primers (with mercury?), and I wonder if bores with severe pitting can be tested for integrity in any way? Maybe like engine cylinder heads with magnafluxing?

Any 'smiths on the boards here? (yeah, I know - everyone is ) Seriously tho'...

[Hoss]

We use it in the car racing game.
Its great for spotting small surface cracks that might lead to total failure. But some stressed parts fail from the inside out!
If the bore is pitted it,ll show up like christmas lights and give you the willies!
Dont know about modern guns but barrels like my 08 MG are soft gun metal for a reason, to prevent cracks.

Regards
Eric

[Bradley Smith]

While not necessarily the type of smith you were requesting, I'll say I wouldn't trust a severely pitted bore. From a metallurgic and physics point of view, a cylinder (the bore) gets it's strength from lacking corners, as corners are stress points. A close examination will reveal that even the rifling has radius-ed transitions. Pitting digs into that cylinder and undermines it's integrity. The pressure inside when fired will force in all directions, including inside that pit, trying to spread it open. More pits, more weakness. Have it examined by a professional gunsmith for a more knowledgeable opinion.

If it's bad enough for you to term severe, I'd say park it for safety's sake.

[Johnny Peppers]

Several years back the American Rifleman had an article on sporter weight barrels. The test was to see how thin a barrel could be turned before it failed. The barrel was turned down and fired until it became impossibly thin, but still held. Finally it was turned so thin that the image of the rifling showed on the outside of the barrel when fired. This was turned down and the barrel failed, but not catastrophically.
Most military barrels are pretty beefy, and it would be hard to imagine one so pitted it would fail simply from loss of integrity.
Springfield Armory had a problem with barrels bursting in the chamber area, but it was found the barrels were contractor made during WWI. Instead of rolling the bars of steel down to approximate finished size, the contractor started with a blank slightly larger than the finished barrel, and bumped the chamber area up in size. This led to flaws in the steel, and some failed.

[JasonA]

This is good information. While I've only held out for excellent + bore weapons, I've always thought that these military pieces were fairly robust. After all, they were made to reliably operate under some of the worst conditions.

In any event, I think that having things checked out by a gunsmith is always the prudent course of action, as others have recommended. Especially if there is any doubt.

Best regards,

J-

[Johnny Peppers]

In "Hatcher's Notebook" General Hatcher tells about turning down the chamber area just ahead of the barrel shoulder to 1/16 inch thick. The barrel fired service rounds with no problem. When one of the proof rounds at about 70,000 pounds was fired the chamber failed.