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…………..SUGESTED TESTS FOR OSR IN SINGLE TEST BARRELS

The tests you are considering are food for thought, and may shed some light. The strain gauge would have to be done at every inch of the barrel from the end of the chamber to the muzzle. This is because all the OSR I’ve seen has been in different places down the length of the barrel. Not only that but I have never seen , nor heard of OSR on a single barrel. IMO, the reason for this is, first because most single barrels are thicker for the full length of the barrel, “AND” the single barrels are not “TIED” to anything for their full length. I think since OSR is not the most common damage to DOUBLE RIFLE barrels which is the separating of barrels from their ribs, and wedges. The barrels of a double rifle do not experience the common barrel harmonics of a single barrel, simply they are tied to the ribs, and wedges, and to the other barrel. This bars the so-called whipping of the barrel as the bullet passes through it that is experienced with a single barrel. So IMO, to make the test legitimate, one would not only have to have proper steel, proper wall thickness, and be tied to another barrel, ribs, and wedges. The barrel profile could be determined by simply measuring a batch of double rifles of a given caliber, and average it out. The biggest problem would be getting barrels of the proper steel. Most of the older barrels would have cut rifling, while new one for the most part will be Cold hammer forged over a tungsten mandrel..

The fact is, as well, it is not chamber pressure that causes the damage to double rifle barrels, or any barrel for that matter, caused by improperly made mono-metal bullets, but the fact is that the barrel’s rifling can’t adequately engrave the hard solid metal, and is stressed beyond it’s capacity to retract after the bullet passes through the bore. This could be a cumulative effect, or may be one of the “STRAW THAT BROKE THE CAMEL’S BACK” thing. Butit is easier for the barrel to expand when both sides are equal but in a double it is far easier to expand on one side than the other when the bullet is passing a place in the barrel where a wedge is between the two barrels. So the barrle is stressed beyond is make up on one side! The side that can be seen from the outside.

All bullet cause a temporary swelling of the barrel (like an egg passing through a snake) as the bullet passes through the barrel, but the ease of the swaging of the bullet by the bore, is easier with bullets of lead core, or with properly cut pressure rings, to allow the displaced metal to flow into the grooves between the rings, than with a solid that is simply too hard to be swaged at all, along with no place for the metal to go that is displaced by the rifling.

The pictures of OSR are photographable, but it is not easy. I have used one method to see the OSR with the naked eye, that could be used to photograph it. The barrel can be coated with a very light film of oil, then dusted with a light coating of talcum powder on the barrel. Now take a cloth glued to a flat hard piece of plastic about 5” wide, and wipe the cloth down the barrel so the cloth doesn‘t touch the low places, but only wipes the tops of any protrusions. This leaver the oil & talcum between the bulges cause by the OSR. This can be photographed by taking the picture at an acute angle down the barrel, with a defused light source, and no flash.

Now I will withdraw again because I seem to be a bug in a couple of poster’s craw, and I don’t want to be a distraction to turn this from a debate to a pissing contest!
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..........Mac >>>===(x)===>
DUGABOY1, and MacD37 founding member of DRSS www.doublerifleshooterssociety.com
"If I die today, I have had a life well spent, for I've been to see the Elephant, and smelled the smoke of Africa!"

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