barrel thickness

[troy_mclure]

i was cleaning my secondary home defence gun today, its a Springfield/J. Stevens sxs in 12ga, chambered for 2 3/4".

history:
this gun is at least 30 yrs old, my dad cracked the bbl shooting too much steel thru it 20 yrs ago, he then sawed the bbl off at 18 3/4" for a rabbit gun.
3 yrs ago i dug it out of the closet where it sat for 15 yrs. i put some new furniture on it, and some fresh blue.

i havent fired it much, but this has me worried.

notice the difference in bbl thickness? is it safe to continue to shoot? is the different thicknesses from wear or manf processes?

[hogdogs]

That gave me chicken skin lookin at that... i look forward to the 'smith type guys to post about it too!
Brent

[jrothWA]

old barrels. You may want to try e-gun parts to see if a spare set of barrel might be had? Not sure what is needed to fit them.

[Dave McC]

Not uncommon, and USUALLY safe to shoot.

But, the penalty for being wrong is severe.

Let Mr Gunsmith take a look.

[BigJimP]

I can't say I've ever hacksawed a barrel off to check it - and all I can say is take it to a reputable gunsmith ( not a garage hack ) and see what they can tell you.

[troy_mclure]

honestly, i dont think the gun is worth the price of the gunsmith to check it.

[BigJimP]

Its your hands and eyes - but I wouldn't shoot it unless it was checked.

I hope nothing ever happens.

[TheNatureBoy]

I have a J Stevens 12ga. 94A single shot and after reading your post I checked my barrel and it appears to be in good shape. I can see it going both ways to tell you the truth. Too much steel or manufacturers defect. Just out of curiosity, how does the inside of the barrel look? At any rate, if you intend to fire it again I'd get a reputable gunny to take a look at it before I did.

[zippy13]

Originally Posted by troy mclure

...notice the difference in bbl thickness? is it safe to continue to shoot? is the different thicknesses from wear or manf processes?

It's from the manufacturing process, not wear. If you know a little how a traditional shotgun barrel is made, you'll understand how the eccentricity might occur. Between the forge and the finished product, barrels undergo significant dimensional changes. In a perfect world, the wall thickness is uniform.
As barrels are struck towards their final profile, the filer has just the muzzle and chamber as a visual reference. Time taken to gauge wall thickness, and straighten the barrel is time away from the file. Of course, the more man-hours budgeted for this process, the more accurate the barrel.
If all shotguns, of the same model, were identical, it wouldn't be necessary to proof every one. Since there are inherent differences, it wise that everyone is proof tested. By shortening the barrel the pressure curve will change. In the original configuration, the maximum muzzle stress typically occurs after powder burn out and the pressure is declining. With the shortened barrel, the maximum pressure is typically reduced; however, the maximum muzzle stress is higher since it's now closer to the maximum pressure area.
Muzzle stress is important because that's where failure frequently occurs. Think of the barrel as stack of very thin rings. As the pressure wave passes each ring, it has a neighbor on each side to help resist the force. Except the final ring has only one neighbor helping. And the next to the last ring has a good neighbor and a weak one, etc. With early firearms, muzzles were frequently reinforced with additional material. We're all familiar with muzzle swell of the bronze Napoleon Cannon.
Dave McC's

Not uncommon, and USUALLY safe to shoot.

But, the penalty for being wrong is severe.

Let Mr Gunsmith take a look.

is sound advice.