Over Stressed Rifling--a nonbeliever has now seen it!

 OSR UPDATE. I stand corrected. The last day of the SCI show Graeme Wright came to the Zimbabwe Professional Hunter's Association's table and asked if I had a few minutes. I walked with him to meet a fellow who showed me his Hollis .450-400 3" double rifle--most likely a pre-WWI rifle. Graeme said this was an example of over stressed rifling and asked me to look at the outside of the right barrel by holding it up to the light and seeing the light reflecting down the length of the exterior. I saw an uninterrupted line of light from muzzle to breech. Next I held the rifle to the light and down the left barrel. Sure enough the line of reflected light was cut by shadows not quite perpendicular to the light but at an angle. This was not visible to the eye when held any other way and could not be felt by the fingers and I doubt it could be measured. Graeme mentioned this was a mild case of OSR and he has seen far worse. I was amazed. I looked over and over again, comparing both barrels, and there was no doubt about it--it was there.

Now, the main question (and one I can't answer) was WHY it was there. The owner of the rifle said it was due to a Barnes solid bullet of the old style with the solid shank--no grooves or bands. He was very upset and I asked him to come to Barnes with me to discuss the matter. He was too angry to do this even though this happened to his rifle approximately 20 years ago. So, back to the question of why. I have no information as to the bullet, the velocity it was shot at, the powder charge, pressure, diameter, etc...

Graeme had an interesting theory. In Australia, where they have lots of doubles, they have Woodleigh bullets and the soft nose, lead-cored, bullets work just fine. In the states, however, Woodleighs were not available in any great quantity years ago and American shooters shot Barnes and other monolithic bullets such as A-Square. So, we may have more problems of this nature here in the states. 

That being said, I will be honest with the readers of this site. I have shot Barnes banded solids 100 times in my Wilkes with no problem and upon my return to Alaska I will examine the barrels as I did in Reno today. Even though I am witness to this in the one rifle I saw I will still stand by my former statements that with the banded solids that are .002" undersize and with the bands to lessen pressure and allow for displaced metal to flow they are fine to shoot. At least in my rifle, anyway. Graeme stated this may be the answer--a bit undersize and with bands--but the older solids were a hard metal and the solid shank did cause higher pressure.

I don't know if pressure is the culprit or the fluidity of the metal. I'm not a metallurgist. Older steels are softer than modern steel. Double rifle barrel walls are thinner than many modern rifles. My .600 barrel walls are much thicker than the .450-400's walls I saw today. That's all I can tell you and that is what I saw. I will post this to the forums upon my return home.

The photo at the top of this post is a pair of Barnes Banded Solids I shot through my .600 Wilkes. It is two of about 100 shots and not a sign of OSR. The answer (I agree with Graeme) is the bands and an undersize bullet. I had enough confidence to shoot them through my vintage .600 and they worked fine with no damage to my rifle.
Cal