Gunsmithing Marks in Barrel

[Cole440]

You know what they say don't you? Don't start looking in there with a borescope or you'll find something!

Anybody have any ideas what this mark is? if I didn't know any better I would say it looks like porosity in the blank or something...

This is a button rifled barrel from a reputable mfg. 304 Stainless. 6.5 mm Bore. I chambered the barrel.
This is around one inch forward of the throat, which had me worried that I had done this with the reamer bushing. But the more I look, the more I doubt that.

Any thoughts?

 

[The King]

Probably the gun drill chasing an imperfection in the grain of the steel or a chip getting caught.

Does it shoot good?

 

[Steel head]

How’s it shoot?

 

[Cole440]

Probably the gun drill chasing an imperfection in the grain of the steel or a chip getting caught.

Does it shoot good?

Yeah, it shoots fine. This is more just curiosity. Especially since I did the chambering job.

It shot under half inch @100 right out of the gate with random Sierra book loads.
I'm just now working up a load but the prospect of getting it under 3/8 doesn't look unreasonable.

My guess is that since there's still around 24 inches of barrel after this, and the throat is clean, it probably has nearly zero effect on anything downrange.

 

[longshot2000]

Do enjoy bratwurtst ? You don't want to look at the ingredients.

 

[BoltRunner]

The Borescope... One of the best and worst things someone can own ... I have genuine OCD so buying a borescope was a terrible Idea for me at first, now I use it strictly for cleaning and making sure I'm getting all the carbon/copper fouling out. I had to finally give in to others suggestions of if it shoots good move on. I have a couple 260 Rem Barrels that have 3,000rds on them and the throats look like hammered shit, firecracking like no other but they still shot lights out till one day the speeds started to drop drastically and then groups opened up and I knew it was time. I have also had some brand new Bartlein and Benchmark barrels that have had some imperfections like this in there that I didn't like but it didn't affect the groups or speeds so I wrote it off and moved on...

 

[The King]

I use the borescope only for consistent cleaning as well

 

[Wannashootit]

Look at some Savage barrels (that'll often shoot 1/2-3/4) and you'll understand that most of it is noise/irrelevant minutiae that makes for interesting internet bullshitting but little practical relevance unless you're a benchrest shooter that chases teeny tiny groups.

I never even look at blanks when they come in. I use it to check the chambers and throats for machining artifacts and concentricity after chambering.

 

[Dolomite_Supafly]

Look at some Savage barrels (that'll often shoot 1/2-3/4) and you'll understand that most of it is noise/irrelevant minutiae that makes for interesting internet bullshitting but little practical relevance unless you're a benchrest shooter that chases teeny tiny groups.

I never even look at blanks when they come in. I use it to check the chambers and throats for machining artifacts and concentricity after chambering.

All Savages have massive chatter marks. What makes them a shooter is when they copper evenly. I buy used Savage barrels and scope them. If they have even copper they generally shoot well. If they have patches of copper they generally won't shoot well. First time I looked down one I was dumbfounded that it shot half way decent.

Here is a brand new Kriger:


Here is the inside of a new DSG AR barrel. This one shoots extremely well.


I just bought a "shot out barrel", here is probable why:

The last 6" of barrel looked like this.

 

[Cole440]

All Savages have massive chatter marks. What makes them a shooter is when they copper evenly. I buy used Savage barrels and scope them. If they have even copper they generally shoot well. If they have patches of copper they generally won't shoot well. First time I looked down one I was dumbfounded that it shot half way decent.

Here is a brand new Kriger:
View attachment 7758146View attachment 7758147View attachment 7758148

Here is the inside of a new DSG AR barrel. This one shoots extremely well.
View attachment 7758149View attachment 7758150View attachment 7758151

I just bought a "shot out barrel", here is probable why:
View attachment 7758158
The last 6" of barrel looked like this.

I really appreciate the reference pics!

 

[Cole440]

Look at some Savage barrels (that'll often shoot 1/2-3/4) and you'll understand that most of it is noise/irrelevant minutiae that makes for interesting internet bullshitting but little practical relevance unless you're a benchrest shooter that chases teeny tiny groups.

I never even look at blanks when they come in. I use it to check the chambers and throats for machining artifacts and concentricity after chambering.

Yeah, I have to say, the only reason I have looked at this barrel as hard as I have is because I chambered it.

I think that it is also important to remember that this mark which looks huge on a laptop screen is really tiny in actuality.

 

[Cole440]

The Borescope... One of the best and worst things someone can own ... I have genuine OCD so buying a borescope was a terrible Idea for me at first, now I use it strictly for cleaning and making sure I'm getting all the carbon/copper fouling out. I had to finally give in to others suggestions of if it shoots good move on. I have a couple 260 Rem Barrels that have 3,000rds on them and the throats look like hammered shit, firecracking like no other but they still shot lights out till one day the speeds started to drop drastically and then groups opened up and I knew it was time. I have also had some brand new Bartlein and Benchmark barrels that have had some imperfections like this in there that I didn't like but it didn't affect the groups or speeds so I wrote it off and moved on...

At this point, I try not to look too hard, especially if it shoots. I do use it for cleaning though. They are a game changer for checking cleaning progress!

 

[Dolomite_Supafly]

Yeah, I have to say, the only reason I have looked at this barrel as hard as I have is because I chambered it.

I think that it is also important to remember that this mark which looks huge on a laptop screen is really tiny in actuality.

I use a bore scope as I finish up the chamber. That way if I see a problem I can fix it while it is still on the lathe and indicated.

 

[Matagorda308]

I’ve never seen a barrel with yellow no passing lanes….