Barrel Damage?

Sometimes if oil is not cleaned out properly and a round is fired it overtakes the oil in the barrel and as we all know you can't compress a liquid and it damages the bore with a ring shaped bulge some thing like that.
 
Whatever caused it appears to have taken place after the rifling was cut. Not only that, it also appears to be a continuous, spiral cut, from what I can tell looking at that photo. That means something hard was caught against the wall of the barrel and pushed or pulled while it was turning. If that is indeed the case, I would guess it is not caused by a cleaning brush, or a ring of oil, or anything like that. Perhaps a chip was caught in a brush that was being pushed into the bore at the same time it was being turned by a drill or something? Very strange cut. Let us know if you ever discover what caused it.
 
When cleaning carbon from a very old (1973), not well taken care rifle I found the same marks. I was told they were tooling marks caused by the manufacturing process. How old is this gun?
 
I might as well weigh in on this one..
Frank, your friend's barrel had something really bad happen to it and I just do not know what to tell you except send it to the manufacturer for evaluation or replace the barrel. I have yet to see this kind of damage in a barrel be close to accurate.

most of the spuds I have used were aluminum or nylon coated steel, I do not see this kind of damage coming from even exposed steel spuds for bore sighting. these are sharp and very deep. spuds would be rounded and smashing kinds of damage
a SS brush and drill, I would say, not likely. I would expect to see much more less defined damage than just a few annular rings but never as deep as this damage is.
this damage is screaming hardened steel bur or cutting edge on a tool. the tool only made a little more than one full revolution each time. the more I look at these picks the more I am convinced this is an act of stupidity, ignorance or malicious intent. I am going to weigh heavily on Ignorance or stupidity on this one. these grooves were cut, not abraded, not crushed into the bore, these grooves had to be cut with something meant for cut metal. These grooves remind me of threading tool marks. single point threading tools I used to work with at A.C. Machining.

the more I look and and scrutinize the grooves, this had to be something going around, wobbling, aluminum cleaning rod, grit or hardened steel sliver stuck in an aluminum rod, this is more and more looking like a perfect storm of ignorance

The only other way I can see these grooves could have been made is a drill, a patch covered brush and some silicon carbide abrasive from a blast cabinet.
 
1. OP still needs to respond as to which end of the barrel (at least I have not seen a response...did I miss it?)
2. If it is the muzzle end, I have a problem with the thought a bore sight stud caused the damage shown. My Simmons studs all are polished chrome steel with a brass "spring" retainer. I am not sure about the construction of an adjustable stud but I suspect the 'spring' retainers are brass also. Sliding them in and out or rotating them would NOT make a gouge in the lands and groves like those in the pics the OP posted.
3. See point 1.
Bushnell spuds are stainless when you tighten they expand too the bore like a collet if you don't loosen them before pulling out you just screwed up they are caliber orenited also
 
Sometimes if oil is not cleaned out properly and a round is fired it overtakes the oil in the barrel and as we all know you can't compress a liquid and it damages the bore with a ring shaped bulge some thing like that.
No disrespect to you but I don't believe that myth for two seconds. I mean aside from this particular case I still don't believe that for any case using modern barrel manufacturing methods. The barrel is elastic, otherwise it wouldn't vibrate, and it's because it vibrates that it can be tuned against during load development. It's also not true that liquids can't be compressed, that comes from water being virtually incompressible but the difference is water is just an oxygen molecule because the hydrogen is so small in comparison whereas oil has a long carbon backbone that can definitely be bent and gives room for some compression at these pressures.
 
This is the best explanation ive seen posted. I had exact same thoughts as soon as i seen it.
shep
but whatever caused the marks was also twisted in place. I can't imagine being able to gouge that steel by hand even if you were trying to so it's very mysterious because the owner should remember what he did and it's highly unlikely the manufacturer did this as the poster is pointing out, since it probably would've been smoothed over after a few shots.
 
What do hammer forged barrels look like inside?
The Bushnell spuds are exactly 3in too the colliminator milled slot the spud draws through when tightened if the wrong cal spud is used and it draws all the way through it leaves 3 very sharp edges of the collet in all my years of cleaning working on rifles etc this the only logical explanation I have if that means anything keep us posted op I'm curious
 
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