Gouges in Freebore

[GunnyUSMC]

I built a .223 Rem about 18 months ago and it has been a great shooter. Once i found a load it likes, it can shoot .5 MOA all day. I use it for my F-TR matches with a consistent 197-198 out of 200 at both 600 and 800. The barrel now has appx 1500 rounds through it and still shooting as good as it did at 500 rounds.

When helping a friend figure out an issue with his barrel, i used my borescope to get some pictures of the inside of my barrel as an example. What i saw in my own barrel kinda took me by surprise. Below is a picture of my freebore with several “gouges”. Given that they are evenly spaced, i am assuming they are left over from the original reaming process. Just wondering if anyone has seen this before and can help me confirm and understand where the gouges came from. I am very cautious with my cleaning process and use a very effective bore guide. Again, this rifle/barrel shoots .5 MOA so it doesnt appear to be having any negative effect on accuracy.

Action is the Zermatt Origin
Barrel is the Criterion bull barrel chambered in .223 match. It is a prefit with barrel nut.

 

[Maurygold]

Borescopes are the worst thing to happen to the internet. put them down and go shoot the gun

 

[nopotential]

the "deep " scratch is from the reaming process. the small ones are the beginning of fire cracking that is completely normal as your round count increases.
if it shoots it shoots the best thing you can do is put the bore scope away

 

[diggler1833]

While inconsequential to accuracy, I'm going to also bet that they've been there since the chamber was cut.

 

[GunnyUSMC]

Thanks guys for your feedback

 

[RegionRat]

Most of the view is normal erosion and nothing to worry about.

We typically study the bbl samples in person where the human eye and brain can use motion to "fill in the gaps" of a flat mono image, but to study still photos is difficult. We would follow up with sectioning the barrels and I would put them under a SEM to study the metallurgical composition and erosion effects. With the barrels cut open, a stereo view gave us a better understanding than a mono view since we had depth of field.

The only thing I don't recognize is the artifact I pointed out in the photo. The circumferential marks and the flat grey color band appear to be right at the end of the neck at the step from the neck to the bore. I wouldn't worry about it since the rig sounds like it works just fine.

A bbl like that should go more than 2500 rounds and that is with rapid strings in an AR. One that is only used in slow fire will go much longer. Semper Fi

 

[Baron23]

Borescopes are the worst thing to happen to the internet. put them down and go shoot the gun

He said...clearly...that the gun still shoots great and he was just curious what would cause such a thing....but no, you just got to come from left field and tell him to just shoot it like he needed your view on that

As for your view of borescopes....lol

 

[papershredder]

The only thing I don't recognize is the artifact I pointed out in the photo. The circumferential marks and the flat grey color band appear to be right at the end of the neck at the step from the neck to the bore. I wouldn't worry about it since the rig sounds like it works just fine.

A piloted reamer can peen or burnish the corner of that step, causing that grey band. Or the reamer was made so that transition from neck to bore is angled and not a step and that appearance of the grey band is just a trick of the lighting on that transition angle. The tiny gouges around that grey band are most likely erosion. Those two longer gouges centered with the groove look to be drag marks left behind by the groove tool either from just getting dull, had material loaded up on the cutting edge, or had a shaving stuck to it as it was making it's final passes. All of those defects are at a near microscopic level and nothing to worry about.

He said...clearly...that the gun still shoots great and he was just curious what would cause such a thing....but no, you just got to come from left field and tell him to just shoot it like he needed your view on that

As for your view of borescopes....lol

lol, What causes most people to freak out over borescope images is those images are at a macroscopic level, almost borderline microscopic level, and they're just not used to looking at up close images like that. Hence, why we advise people to throw away their borescopes.