what do you look for when borescoping?

a borescope and a concentricty guage,,,2 things I wish i had never bought!!!! cause they drive me crazy.

anyway, i've had this lyman borescope for a year or so. i've looked thru a couple brand new barrels and some of my super used barrels... i like to look after cleaning just to make sure all looks good. i've come to the conclusion that I am not entirely sure what too look for, you would think a carbon ring would be easy to see and self explanatory but perhaps not... is it normal to find pieces of copper? do they brush out. what does bad copper fouling look like. what does bad carbon build up look like!

any experts on here got any tips. this is related to another thread i started about some unusual pressure problems i am having on a hunting rifle

 

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

 

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.

 

Wow that's a clean image. I've been trying to figure out these. They are in the neck area. (Second shoulder on the left)

OMG at least I don't have that problem

 

what a great image,,, so that is basically a image of what used to be the neck? and the lip on the left is where the neck ends and the throat starts? so the bullet would travel from right to left looking at the pic? or am i getting it backwards

 

Left to rt. end of chamber neck on left. No carbon farther down the barrel. I though the carbon would be a little farther down the barrel but the barrel was roasted. Don't know what it would look like if there was decent rifling.

 

If barrel sellers had borescopes for rental I think they'd up their sales dramatically.

 

As Texas10 says, borescopes are the salesperson for the barrel maker.

 

I find all kinds of uses for bore scopes other than looking at barrels, which I only do to see how clean the bore is. Ever look inside your bolt? check your neck clearance? Check out the inside of a die? Every now and then a problem pops up and being able to take a close look is helpful.

Now if you're the type to freak out over every little squiggle in a piece of steel, burr, or spot of rust, don't bother. You'll go nuts.

 

That's what I've been saying , you can buy a bore scope but you have to know what to look for . I bought the Hornady Bore Scope , not the top of the line scope but good enough . Wish I had it when my barrel was brand new to compare . What does wear look like , yes you can see heat cracks as time goes on but what is normal and what is a washed out barrel . Good for seeing carbon or copper . I'll have a better idea with my next barrel change. Other then that my barrel looks clean and shiny. Worn out , I don't know.

 

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

 

does the copper ring look different than the carbon ring? are they in the same place?

 

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.

 

this is a great question, i did a lot of searching on the interweb and there just doesn't seem to be a consensus out there. no suprise.

 

I am by no means an expert on a bore scope, but am glad I own a Hawkeye. It is rare that I inspect a new barrel, no way can I decipher inclusions or anomalies from tooling marks. I get a new chambering, first I dab some Kroil on a couple jag patches and clean any chambering oil residue out.
Then I'll load some velocity test rds to see what speeds can be accomplished, 16 is the most ever, with the help of QL. When I am done, the borescope comes out and I check for carbon and copper buildups. Where they start, end, etc... , because any trend will most likely carry the life of the barrel. Unless you are way better at it than myself, with a Hawkeye I cannot tell the depths off any build up, but scoping after a cleaning may help here.
If a guy does not learn a few things from a BS, no use owning or using one. Certain powders lay down serious hard carbon in the first 6" of the barrel(H4895, RL 16), and some seem to foul the muzzle end(Varget, H1000, Retumbo) and along with copper deposits that accompany muzzle buildups.
I have been able to smooth out a couple rough areas with JB that were stripping copper for no reason, and results were darn positive.
I do not use it to decipher throat erosion, seems like a guessing game you cannot do much about anyway, get a pressure dump redo the load. I have the means to check this another way.

On the concentricity gauge not getting much use, that is a good thing, better to have and not sell than have a situation arise and have to rebuy one. I used mine for the first time in 3 yrs this past week, on something questionable, I was dang glad to have the 21st Century. It answered every question I had.

 

To me a carbon ring forms at the end of the neck in the chamber, the 45deg angle leading into the leade or freebore of the barrel. IMO, be tough for any ring or buildup to form in bulk in the bore in front of 58-65K of pressure every time you pull a trigger.

 

Interesting question. I will not pull it out unless I am having a problem on paper. I am generally looking for build up around the throat or at the end of the muzzle.

Trying to figure out the effect of wear is a way past my pay grade. There’s not much correlation between what it looks like on the scope and what it looks like on paper.

 

I only have one rifle that builds a carbon ring, but as explained above, is exactly where it builds its carbon ring. When I'm checking OAL to touching, I can feel the carbon ring dragging on the bullet as I'm pushing the bullet up in to touching the lands. First time I felt it, it kind of freaked me out a little so I got out my Lyman borescope and sure enough, carbon ring had built up just before the freebore area.

My Lyman borescope was the best $200 I ever spent. I wouldn't mind having a Hawkeye borescope some day, but for now, the Lyman does me well and I'm glad to have it.

 

No lust appears as dark circle, the same place,from the end of the neck to start of throat

 

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.