what do you look for when borescoping?

[Milo 2.0]

So before, in or after the freebore area? In the pics I posted (which I will admit aren't the best) there appears to be an undulation in the portion of the neck just before the beginning of the freebore. It would be just ahead of the case mouth but before the freebore. Varget204 is suggesting it's right where I see the anomaly in my pics.

Milo - what 45 degree angle is there between the neck and the freebore? I have always understood the following terminology: neck, freebore, leade (the ramp to the...), lands/rifling.

I can find a reamer print, but probably cannot draw an arrow to show you, but yes, neck to freebore or leade, but the neck is considerably bigger in dia than the bore, the 45deg is the taper making that transition.

 

[Milo 2.0]

Here

 

[varget204]

I'm wondering about what I see in the neck area of my chamber. There seems to be a lot of wear between where the case mouth would end and the beginning of the freebore area. These pics are about as good as I can get on my Lyman.

Your pic on left shows C/C ring,starts leftside of clear metal goes to start of freebore,what you are calling 45 deg angle

 

[newbieshooter]

Where would a carbon ring appear? In the neck area, freebore or leade?

http://forum.accurateshooter.com/threads/carbon-ring-what-is-it-where-is-it.3912845/ (post #10 - Illustration).

 

[dkhunt14]

Your pic on left shows C/C ring,starts leftside of clear metal goes to start of freebore,what you are calling 45 deg angle

I also see carbon starting to build up in the neck area of chamber. I also see the normal firecracking where the neck area ends. Carbon can also build up in leade and that's where it gets real hard from heat and bullets passing over it. When it happens there, it can take days of soaking and mechanical cleaning from Iosso or JB. Matt

 

[dmoran]

 

[JMayo]

I look for anything that is black, ragged and/or color change.

Just looking around. Remembering a spider web thickness looks like a canyon . . Squiggly spots can be leftover cleaner.

I guess figuring out what is nothing is the big mystery ...

 

[SGK]

ok so sounds like my pics are an example of what to look for with a borescope! I will compare it with a lower shot count 223 barrel of same manufacturer and an un-shot Bartlein I have.

Sounds like I need to try to clear that carbon from the neck...

 

[atblis]

 

[muleman69]

This was great, can we get this with Audio ?

 

[rockwind1]

at blis, is that your video? and gun?

 

[rockwind1]

that is a great video. if only someone could put that down some rifles that are having all the indications of a carbon ring, or have been diagnosed with a carbon ring, and see what the darn thing looks like!

 

[BDman]

Uhhh, the crown looks good. I was raised to always say something nice...

 

[dcali]

that is a great video. if only someone could put that down some rifles that are having all the indications of a carbon ring, or have been diagnosed with a carbon ring, and see what the darn thing looks like!

You’ll know it when you see it. Look at the picture dmoran posted above. That blue ring of gunk that piles up at the end of the neck sticks out like a sore thumb when you see it. Clean the barrel, then scope it. You will see it if it’s there.

 

[atblis]

After some cleaning

Part II: Wipeout/Patchout

Part III: JB bore paste

 

[LGKLAS]

This is an image I took at 25X on a scanning electron microscope on a cross-sectioned 6mm. Rem Douglas barrel with over 5000 shoots. On the left is the end of the case mouth. The bore was cleaned only by running patches down the bore. I guess this constitutes a carbon ring. Energy Dispersive Spectroscopy was used to verify the debris was carbon. No evidence of rifling for almost 2".

Added later:
I used a brush then patches to clean the bore.

View attachment 1122695

Out of curiosity and at risk of asking dumb question, how did that rifle (barrel) shoot? No rifling for 2" is quite a 'jump'.

 

[LGKLAS]

1st thing i look for is carbon/copper ring at back of throat. It's a dark grey/blackish ring,in borescope.Have not seen any copper pieces,have seen copper streaks in some of the grooves in some barrels.A brush and patch w/copper cleaner will remove it.Would think,one had a rough spot ,if pieces of copper are found in barrel.Before i got my Lyman borescope i cleaned all my rifles untill patches came out clean,NEVER Knowing i was Leaving carbon/copper ring at back of throat,now i use a [.neck diameter] nylon brush w/ cleaner on it in throat area to remove it.If you let it build up,it effects accuracy and gets like concrete,hard to remove

I have the same borescope and happy to have it. I look for: carbon ring, copper build up in the rifling, and carbon up/down the length of barrel. I've identified carbon rings and copper build up and a large amount of carbon build up on the edge of the gas port in my AR. Alll of which I was able to remediate with the proper chemicals. Wipe-out foam. A studied and judicious use of CLR. Etc.

When I first got my scope, I had a new , never fired, rifle or barrel (can't remember which for sure). So, I scoped that and took pics along the way. That gave me a guide as to what to look for. I could compare photos taken of guns that had been fired to the new barrel. That taught me what to look for.

Concentricity gage- I have one too. It sits on my bench most the time; because since I got my Forster Coax press and their Microseating die my bullet runout has been 0.001" or less. So rarely use it to check RO.

Looks like you got some good answers so FWIW. lg

 

[atblis]

Out of curiosity and at risk of asking dumb question, how did that rifle (barrel) shoot? No rifling for 2" is quite a 'jump'.

3/4 moa

Eta: I don't think it's a 2 inch jump. I'd guess 1/2 inch.

 

[SGK]

It was Webster's rifle that had no rifling for 2"

 

[LGKLAS]

It was Webster's rifle that had no rifling for 2"

Okay thanx!!