doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com THAT was close

I voted the "obstruction" answer on page one, post #675,773. I'm sticking with it.

So in summary I think Bill is probably correct. The arrows point to a ring bulge



But I think William is correct also. Frequently the burst is a combination of factors. The image above is from an abused gun shot with Sellier & Bellot 1 1/4 oz. shells of unknown pressure (likely CIP max.) known to have squib loads, AND IMHO the wall thickness is suspect.

One can be confident as to the cause (IF the wall thicknesses are measured) if the barrel looks like this



What about this? Looks like a ring bulge?



Or not, and I doubt it the barrel left Parker Bros. with that wall thickness. Another time bomb damascus barrel for Harry



I will stand by my statement that long splits (in a shotgun barrel) are typically from thin walls; L.C. Smith Long Range. I don't know the pressure of the 3" Winchester Bismuth load but likely SAMMI max.



The frustrating problem, for those of us trying to learn something, is that images get posted of a "blow up" but no one seems willing to measure the wall thicknesses

Thanks to Randy I have contacted the seller of Flues. We'll see.

Learning something, and maybe a word of warning, is the point. Smith Field with 1 3/8 oz. Bismuth

I have Damascus guns with monster thickness (like 50k!) and others with only 17k (out near the muzzles). Clearly I use them differently, but I never give the heavy ones a second thought (as far as their safety is concerned) even if some are very old (124 years is my youngest) and Twist even(!).

The sad part is that it's hard enough just to get an accurate barrel length measurement from an internet gun seller. Far fewer people own a micrometer or vernier caliper than people who own (and can actually read) a tape measure. In addition, a regular micrometer or vernier caliper isn't very good for reading the thickness of a concave curved surface anyway, which is why barrel wall thickness tools have a small rounded piece opposite of the dial indicator.

I'm not sure exactly how it relates to shotgun barrel failures, but when newly manufactured smaller diameter steel pipe or seamless steel tubing fails during hydro-testing, virtually all of the failures I've seen are longitudinal splits. Since a gun barrel in normal use is open ended, it seems hoop stress may be a bigger factor than longitudinal stress, even with a light obstruction. The same seems to hold true for the majority of shotgun barrel failures. However, some barrels may have internal defects, or deep visible pitting, or localized exceptionally thin spots that may exhibit failure somewhat differently. It's rare to see any sort of grenade type shrapnel being ejected in a "normal" burst scenario. I'm sure many of us have seen photos of rifle barrels that had multiple longitudinal splits due to barrel obstructions and much higher pressures. About 20 years ago, I had the pleasure of spending nearly two days getting frequent showers of cold river water while working on a Hydro-tester that was over-pressurizing pipes after the wrong program had been inadvertently loaded into the PLC. I got to see more failures in a couple days than the machine operator would normally see in months.

However, those of us who mostly shoot break open doubles have the distinct advantage that we can use our brains and take a quick look for bore obstructions every time we reload. Falling while hunting, and poking our barrels into snow or mud should be a no-brainer time to check the bores, and a blooper should arouse our suspicions of an obstructed bore too. I've told the story of quickly loading my single shot Savage garage gun to shoot a groundhog near my garden. But just as I was about to pull the trigger, something told me I should check the barrel. I backed into the garage and unloaded, and found the barrel was totally plugged with hard mud from a mud dauber wasp nest.

That's heavy load. I looked at identical components loads fron reloading manual with only difference being bismuth vs. lead. The bismuth load was higher pressure probably do to harder pellets.

Splain that, Mr. "Jagermeister".