I've seen barrels that were over stressed and looking down the bore the rings were easily recognized.
I've seen "stress" rings when it was nothing more them bad lighting.
Then there are times that I don't know what the heck I'm looking at.
Does looking down the bore using a 12guage shell with the primer cap removed at the breech end and a 20 gauge with primer removed at the muzzle end give an accurate indication of stress rings?
My shooting student Joe Wood taught me to look at a paned window (or something similar) and hold the barrel where the line from one of the mullions (sp) goes from muzzle to breech (on the outside of the barrel). Then roll the barrel (looking at the outside). Any ring bulges show up as a bump in that otherwise straight line and can be followed around the barrel.
I know I explained that badly but give it a try. I have confidence in my ability to spot a ring bulge.
Best,
Mike
I'm not sure I'm familiar with the term "stress ring." I do know what a ring bulge looks like, and they are easy to spot. If you are referring to rings or marks in the bore what you're probably seeing is evidence of a poorly applied hone.
eeb I have seen ring bulges that are very subtle. Had I failed to go through the process I described and I would have missed them.
Best,
Mike
eeb I have seen ring bulges that are very subtle. Had I failed to go through the process I described and I would have missed them.
But you are right, I assumed Pooch meant ring bulges when he said stress rings.
Best,
Mike
Pretend you're looking down a pool cue.
The stress rings I'm referring to is when the metal of the barrel has been "stressed" or deformed, the light will cause a series of rings will appear on the inside of the barrel. I believe it is caused by the light undergoing a slight shift when it hits the metal that has a different molecular structure then the metal beside it. The rings are a signal to look for anomalies in the barrel, or a better lighting source. The rings can be an indication of a slight bulge that one would ordinarily miss or an indication of the metal of the barrel being worked by either age, fatigue or over pressures.
Sun light is the best light source as florescent lighting often can give a false ringing.
Pooch, You might be referring to 'rivelling'. There is a thread on this from about a year ago. A rivelled barrel is pretty much a shipwrecked barrel....very few can be remedied, but I guess a few can. A rivelled barrel will not pass proof in the UK unless remedied, which I understand is very hard to do. Cause of rivelling is unknown, but a possibility includes shooting 'boomers' in guns with thin barrel walls. There are other theories as well.
Rivelling thanks, boomers in thin barrels is a definite suspect. Severe riveling is readily apparent, but most often one sees a light "ringing" not the series one sees in a rivelled barrel ie few cases of refracted lighting. In the case of few rings, I believe there is damage, but not fatal damage to the barrel. I see it like having a mild heart attack, you can have a life but your racing days are over. It does mean using low pressures and light loads in the gun.
How can I find that thread as I would like more information, it is a difficult subject. Thanks
The thread is from 6-8-11. Sorry, I don't know how to pull it up for you. There is an excellent chapter in "Shotgun Technicana", By David Trevallion, on rivelling, if you have access to that book. BTW, there is a wealth of knowledge in that book.
As difficult as interpreting rivelling in a barrel. Interpretation the rings or light refraction in the barrel is more difficult. The light ring is caused by an anomaly in the barrel. The question is the anomaly a fatal one or one you can live with.
Pooch
what you are saying makes sence to me. Sounds like a good way to check it.
Monty
As difficult as interpreting rivelling in a barrel. Interpretation the rings or light refraction in the barrel is more difficult. The light ring is caused by an anomaly in the barrel. The question is the anomaly a fatal one or one you can live with.
Generally, if the ribs are tight, I would not worry about this kind of small ring bulging, from a safety concern.
You are probably mostly right. I do think you ought to back off on the loads.
There are a number of copies of Shotgun Technicana on Amazon.com... from $100 to $1100+ !!
I'm not overly fond of McIntosh for reasons of my own. I won't be buying that book.
Pooch,
If you want to back off even more from a conservative load, that's a personal choice and sure won't hurt anything. But my opinion is that the barrels themselves are not weakened from this condition. But if you are trading utility of the gun in order to back off your load, I would say it is not necessary for this condition. A quick look at some stress-strain curves for steels of similar strength will show that strength from this type of deformation is actually increased, not decreased, albeit a very small amount.
There are literally millions of products made from cold formed steels of similar charateristics to barrel steels. Many of these products carry critical loads. An example is hydraulic and fuel hardlines in airplanes. These lines are made from steel tubing. They are cold formed (bent) to fit the routing in the airplane. The deformation is many times more from this bending than a small bulge in a barrel. The function of these lines are critical to the normal operation of the airplane. These thin little hydraulic lines operate at 3000 psi with pulse spikes to much higher.
...I believe it is caused by the light undergoing a slight shift when it hits the metal that has a different molecular structure then the metal beside it...
You mentioned that this may be a sign of deformation in the barrel but you seem to feel the tube is true. I think you are seeing deformation, but if the barrel is true, I don't know if differences in surface appearance could lead to significant conclusions. The book that was mentioned might be worth checking. You may not prefer one of the authors, but I think there is meaningful contribution by the coauthor.
G.T. Garwood has an illustration of barrel rivelling in one of his books. The photo was taken after striking off the barrel blue with a sanding block, the absence of blue on the high points clearly indicating the presence of a series of physical prominences or corrugations in the barrel wall. The angle of incidence and reflection of light from a shotgun bore is a very pretty thing and the relative concentricity of the rings has been said to prove a number of things about the barrels (straitness, relative vertical regulation of sxs barrels) but I've never encountered anyone who claimed to identify changes in the molecular architecture of an apparently homogenous material with the naked eye. I doubt if Thomas or Trevallion have either.
jack
Light bounces differently from different surfaces. I presumed that was the reason for the ringing.
Dang Chuck H now I'm really confused.
Is anybody familiar with using a 12 ga empty with the cap out and a 20 ga empty with the cap out at the muzzle to see the ringing better?
After looking down a slew of barrels I knew were right. I've come to the following conclusions. Sun light is the only dependable source as artificial lighting will cause refraction. Even if you get a couple of rings it doesn't mean much. Just inspect the barrel more closely. A riffled barrel will readily show up.
I been following a false trail