Help me interpret this borescope video: fire cracking, carbon ring, throat erosion

[new2mud]

Barrel is a stainless 6.5 PRC w/ 0.188 freebore right at 600 rounds through it. Mostly handloads of 147 ELD-M and Berger 156 EOL with N565 powder until the recent (last 50 rounds) switch to H1000.



My questions:

1. How bad is this firecracking?
2. Do you see evidence of the dreaded carbon ring?
3. Based on what appears to be the distinct ring where the chamber cutter ended and the lands are tapered, how much throat erosion is apparent?

First--it's your fault--this forum is what informed me about the low-cost Teslong borescope, and kids just got me one for my birthday—awesome.
And yes, I realize that every newbie with a borescope is now a barrel hypocondriac!

But it's cool, and informative to know what's going on inside the bore.

And now videos like this enable folks like me to learn from the experienced smiths and folks like you on this forum that have more years looking down barrels. (From the chamber end)

 

[OG10]

How does it shoot ? I have rifles that are much worse, they still hold moa.If accuracy drops off set it back or rebarrel. Barrels are expendable commodities good luck dont stress and carry on.

 

[Rick Richard]

Evidence of Fire cracking and throat erosion for sure, how bad is it? I have seen worse. I would say you have around half or little more of barrel life. if accuracy is not effected, just keep it clean and continue shooting.

No carbon ring in my opinion.

 

[new2mud]

It shoots fine, and I wasn't concerned about it when I posted. Accuracy has slightly dropped off (still holds .6-.7 fine) but I haven't tried loading longer yet. That's next.

I'm just wanting to learn from you all what to look for and what "bad" and "not bad" look like.

 

[Mram10us]

Most of that is carbon. Scared myself when I got a borescope. Bad carbon ring which is probably affecting Your pressure. Bronze brush with carbon cleaner will fix it

 

[new2mud]

Most of that is carbon. Scared myself when I got a borescope. Bad carbon ring which is probably affecting Your pressure. Bronze brush with carbon cleaner will fix it

Is the carbon ring what I refer to as "fire cracking" in the video? Or is it something else? Still learning here.

 

[Rick Richard]

Most of that is carbon. Scared myself when I got a borescope. Bad carbon ring which is probably affecting Your pressure. Bronze brush with carbon cleaner will fix it

Hey brother,
Don't disagree there is some carbon there, but that is not a carbon ring in my opinion. A carbon ring that effects pressure is usually a build up of a narrower ring at the junction of the chamber where it transfers to the rifling and slightly passed that. My interpretation anyway.

 

[Mram10us]

Hey brother,
Don't disagree there is some carbon there, but that is not a carbon ring in my opinion. A carbon ring that effects pressure is usually a build up of a narrower ring at the junction of the chamber where it transfers to the rifling and slightly passed that. My interpretation anyway.

All good, Sir. It sure looks like what I consider a carbon ring in the end of the neck, but maybe my definition is off. I'd still remove it and all the carbon in the barrel and see what It looks like.

 

[Mram10us]

Is the carbon ring what I refer to as "fire cracking" in the video? Or is it something else? Still learning here.

What you called the "case end" is what I was calling a carbon ring. First couple seconds of your video are it.

 

[CVCOBRA1]

Did you scope it before you fired it?
Sell your bore scope.

 

[new2mud]

Did you scope it before you fired it?
Sell your bore scope.

Haha. No I just got the bore scope.

I'm not too OCD so I don't mind a dirty or imperfect bore—I'm just trying to learn when there actually is a problem (eg carbon ring) that needs attention.

 

[new2mud]

What you called the "case end" is what I was calling a carbon ring. First couple seconds of your video are it.

So it seems that what you are calling the carbon ring is the smoother looking section ahead (aft) of the section that others are calling the fire cracked ring (the part that is crackled). I don't think you are both referring to the same section.

Do I have my references correct?

 

[Mram10us]

Hey brother,
Don't disagree there is some carbon there, but that is not a carbon ring in my opinion. A carbon ring that effects pressure is usually a build up of a narrower ring at the junction of the chamber where it transfers to the rifling and slightly passed that. My interpretation anyway.

Rick, what is your definition of a carbon ring? I'm no expert and curious what other consider. Thanks

 

[Wedgy]

You can get carbon affecting pressure anywhere from the case mouth forward but I would generally get them on the edge of the chamber/freebore. I do preventative scrubbing so they don't form which I like better that diagnosing strange pressure and accuracy issues

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