What's this?

[gunsandgunsmithing]

Have a bbl in the shop for a tuner install. It's a new barrel, previously chambered but unfired. Customer asked that I cut 2 inches off and machine for my tuner and of course, recrown.

I do all that and run a bore scope inside to check my work. For starters, there were multiple small inclusions that look a lot like pitting for about an inch and they fade away into a very nice looking bore and chamber job, the rest of the way. Gonna cut that off and do it again, per the customer's request. May shoot great but just the uncertainty was enough for him to say, cut it off.

Now the question... What is this ring around the bore? It's pretty uniform and on both lands and grooves, so it's not a range rod or anything I did. Or, at least I have no idea how I could have on both lands and grooves.

Here's a Pic. It's very faint but noticeable. The Pic makes it look worse than it is. It's all the way around.

 

[Charliemac]

To me it looks like a scratch. It also looks as though whatever it was that scratched the bore skipped at the edge of the land? Where abouts is it in the bore?

 

[DShortt]

Looks like a scratch to me also, but I can't imagine how that could happen since it appears run so close to the bottom of the land/groove junction. That's quite odd looking.

 

[liljoe]

Carbide tip on the indicator?
Joe

 

[wvlongshot]

Button rifled? Maybe something like a rag fiber got pulled across.

 

[gunsandgunsmithing]

Carbide tip on the indicator?
Joe

If so, it was done probably while chambered and it was at least 2 inches inside of the bore, depending on when the smith that chambered it, cut it to length. If he rough cut the blank prior to chambering or reached in at least 2 inches while crowning, it's possible but just doesn't look like an indicator tip damage to me. I agree that an indicator is the most logical but it goes right up to every land and looks too deep to me too, for it to be that.

 

[gunsandgunsmithing]

Button rifled? Maybe something like a rag fiber got pulled across.

Cut rifled.

 

[gunsandgunsmithing]

To me it looks like a scratch. It also looks as though whatever it was that scratched the bore skipped at the edge of the land? Where abouts is it in the bore?

It's now about 1/16th from the crown but that's after I cut 2 inches off. So it had to be there at a little over 2 inches deep.

 

[ronsatspokane]

Tool mark probably from rifling. Not enough to be of concern. Look at a Savage barrel that shoots very well and you'll see how much it would take to affect shooting.

 

[gunsandgunsmithing]

Tool mark probably from rifling. Not enough to be of concern. Look at a Savage barrel that shoots very well and you'll see how much it would take to affect shooting.

Looks like it had to be after it was lapped. It's a top end cut rifled bbl. I mentioned numerous inclusions and what looks like pitting for about an inch as well. I have to wonder if it's somehow related but not sure how. I agree, this looks like a simple scratch and that it may shoot great even with the scratch and pitting.

 

[AlNyhus]

Could that have come from the rifling cutter?

 

[gunsandgunsmithing]

Could that have come from the rifling cutter?

Looks like it had to happen after lapping, to me.

 

[gunsandgunsmithing]

Gonna fix it either way but am just curious if anyone had seen this and maybe knew for sure what would do it. It may remain one of life's great mysteries! Lol!

 

[gunsandgunsmithing]

Looks like a good reason to Borescope a barrel before preforming any work.

I said the same thing. I shoulda. Course, so should the guy that chambered it as well as the bbl maker. That's assuming I didn't do it somehow but I really don't see an opportunity in my process on this one.

 

[243winxb]

It's now about 1/16th from the crown but that's after I cut 2 inches off

A bore sighting tool?

 

[DShortt]

No, that would leave either a barrel bulge toward the muzzle or nothing at all. Most likely a bulge.

That image is something that looks very much like a scratch but the interesting thing is it is in the lands and grooves both, plus it was over 2" into the bore according to the OP. That's a neat trick, whatever it is.

 

[hoz53]

I said the same thing. I shoulda. Course, so should the guy that chambered it as well as the bbl maker. That's assuming I didn't do it somehow but I really don't see an opportunity in my process on this one.

i havent purchased that many barrels but ive allready sent one back(new) that had a land wiped out for a couple inches so i think imperfections happen more than we think. I would wonder what caused that scratch to. but that close to muzzle i would cut it off- mabie you could make up 1/16” at chamber end if its really needed since ur cutting the chamber off.

 

[gunsandgunsmithing]

i havent purchased that many barrels but ive allready sent one back(new) that had a land wiped out for a couple inches so i think imperfections happen more than we think. I would wonder what caused that scratch to. but that close to muzzle i would cut it off- mabie you could make up 1/16” at chamber end if its really needed since ur cutting the chamber off.

Nothing wrong on the chamber end and not cutting that end off. It looks nice. But the pitting that goes for an inch has gotta go too. Customer said cut it off, so I shall. Only an inch to get rid of everything, so not a huge deal. I may post pics of the pitting as well. Not mentioning the bbl maker. Not even sure I know, but the owner may have said. I do think he said it is a cut rifled bbl and it looks like one, so that's all I know really. That ring piqued my curiosity though. Just not sure how it could get there other than an indicator and that seems unlikely too.

 

[gunsandgunsmithing]

A bore sighting tool? My guess.

New bbl, that I don't think has ever been installed yet.

 

[gunsandgunsmithing]

No, that would leave either a barrel bulge toward the muzzle or nothing at all. Most likely a bulge.

That image is something that looks very much like a scratch but the interesting thing is it is in the lands and grooves both, plus it was over 2" into the bore according to the OP. That's a neat trick, whatever it is.

Right on. Just weird but I'll fix it.