Barrel vs borescope, redux

[memilanuk]

So... I was going to piggy back on the other thread here, but since its spiraled off in a different (non technical) direction, I decided to start a new thread of my own.

In the past, I've always just cleaned my barrels til the crud stopped coming out, and the patches stopped coming out blue. Seemed to work.

I bought a 'share' in a borescope at a local gunsmith shop years ago... basically I can go down there, put my barreled action in a jig, and look down it with a Hawkeye. Not too many surprises... some factory barrels that looked horrific but still shot fairly well, a Krieger medium Palma .30 cal barrel with 6k+ rounds was prettty well toast, etc. I always put my name in the hat at the BSWN to try and win the drawing for a new Hawkeye of my own, but no luck

Last year I decided a Lyman borescope would be worth the risk - maybe not the image quality of a Hawkeye, but good enough, and with image capture, for what I wanted.

Couple things I've 'seen' since then have surprised me a lot.

One, my normal routine of cleaning with WipeOut Accelerator + PatchOut til the black/blue stopped coming... was leaving an awful lot of both carbon and copper behind.

Two, the... for lack of a better term... 'burn pattern' or wear/erosion in the barrel looked a lot different than I expected.

Most of my past 'scoping with the Hawkeye had been on .30 cal barrels, shooting predominantly 155 gn bullets, with relatively short bearing surface, being propelled by either Varget or N150. The wear/erosion in those barrels (when cleaned down to more-or-less bare metal) showed some burning/checking erosion on the tops of the lands, some black crud in the corners of the grooves against the lands, and when that stuff was cleaned out, if it was a factory barrel, you could still see the tooling marks basically 'preserved' under the carbon. The center of the grooves was bright and shiny and looked like the main contact surface, as one would expect.

Most of the newer barrels have had a steady diet of 200 Hybrid (and more recently 200.20X) bullets propelled by Varget or H4895. I've looked at one with 2500+ rds thru it (toast), one with ~750 rds thru it, and one with ~200 rds thru it. Two different barrel makers. They all exhibit the same wear/erosion pattern. Little bit of wear on top of the lands, increasing with round count. Bright shiny strips in the corners of the grooves, no carbon trapped in there (good, I guess)... and the part that has me scratching my head... a big wide nasty looking strip of char right down the middle of *every* groove, starting a few inches ahead of the throat, and extending towards the muzzle. How long, and how deep, seems to correspond to the round count.

Basically, the way the barrels look to be eroding is almost the complete opposite of what I would expect, based on what I've seen in previous barrels shooting other (lighter) bullets. Somewhere around here I've got a barrel that had a steady diet of 185 Juggernauts and Varget; I'll have to see if I can find it and clean it up and see which way it looks.

I'm curious... anyone else with a bore scope seen similar burn/erosion with long/heavy bullets (for caliber) vs. short/light? Any ideas on why in the one case, the bottom of the grooves is shiny and polished (metal on metal) where in the other case its charred and burned away in the bottom of the groove before the lands?

 

[msinc]

This "charring" you see in the groove...is it just beyond the throat or does it appear to extend further down the bore???? I have noticed the black stripe in the groove on some of my barrels that shoot longer heavier bullets. Yes, it does not clean out with normal cleaning practice, but in all of mine it will eventually with JB Bore Cleaner. It's almost like the groove gets "blued", but it is not burned, at least not to the point that it wont come out or is actual metal damage.
I should clarify that kind of along the lines of what you are saying, the first thing I discovered with my Hawkeye is that just about every so-called "bore cleaner" made, with the exception of a very few just DO NOT WORK!!!!! I have tried every "shaving cream" looking schidtt made and it ALL amounts to absolutely zero. You would seriously be better off to try Formula 409...at least some of the powder fouling would wipe out.
So, "normal cleaning practice" for me is a good scrubbing with Shooters Choice followed by a couple hour long soak. Once a barrel is "broken in" this usually does it. While breaking in and if I have shot a lot of rounds I sometimes don't have time to do all the soaking and just use JB. The bottom line is that the black stripe in the middle of the groove would not come out with normal cleaning, no matter how long I soaked or how many times I repeated it, but again, in my case it wasn't "damage" per se.
Maybe we are talking about something different???

 

[memilanuk]

This "charring" you see in the groove...is it just beyond the throat or does it appear to extend further down the bore???? I have noticed the black stripe in the groove on some of my barrels that shoot longer heavier bullets. Yes, it does not clean out with normal cleaning practice, but in all of mine it will eventually with JB Bore Cleaner. It's almost like the groove gets "blued", but it is not burned, at least not to the point that it wont come out or is actual metal damage.

As stated above:

...starting a few inches ahead of the throat, and extending towards the muzzle. How long, and how deep, seems to correspond to the round count.​

...the black stripe in the middle of the groove would not come out with normal cleaning, no matter how long I soaked or how many times I repeated it, but again, in my case it wasn't "damage" per se.
Maybe we are talking about something different???

So far I've tried WipeOut Accelerator + WipeOut PatchOut, with an occasional (ever few hundred rounds) of Witch's Brew. Still had the black nasty stuff all over, along with big long copper streaks *in* the black nasty as well as along the lands. The amount of coppering was roughly correlated to the barrel life i.e. the more rounds, the more fouling. Bear in mind, I'm talkin' stuff that *didn't* come out, despite the patches no longer showing black/blue, even after a couple hour soak.

More recently I started using VFG pellets from Brownells, along with Kroil & JB Bore Paste... which did a *much* better, but not complete, job of getting the black nasty out. Still had a few long copper streaks in places, though. I've started using BoreTech Eliminator and Copper Remover... the former seems to work okay, the latter... can't tell much if any difference :/

Despite a fair amount of scrubbing, I still can't get all that black nasty out... and in this case, the metal is most definitely looking eroded. The squeaky clean aspect of it isn't really a priority (it'd be nice, but not essential). I'm more concerned with whats actually going on with the weird burn/erosion areas.

One person I was talking with wondered if it was 'blow by', which at first I thought was nuts, but now, the more I think about it... is making some sense. One of these barrels was being loaded to a higher (hotter) node, and after a while, it suddenly started losing velocity and dropping off that node. Bumped up the powder charge... worked for a while. Then it started dropping off again. Almost like it isn't sealing completely... and if the hot gasses are jetting by the bullet, that would have to be hell on the barrel steel. No idea if that's whats *actually* happening... but who knows?

 

[Alex Wheeler]

Is this char black and shiny? Looks like black chrome? This would be looking in a clean barrel. It may not look shiny with a lyman? But what you are seeing in my opinion is hard carbon. Use some iosso or jb and then bore scope. Solvents will not remove hard carbon.

 

[memilanuk]

Is this char black and shiny? Looks like black chrome? This would be looking in a clean barrel. It may not look shiny with a lyman? But what you are seeing in my opinion is hard carbon. Use some iosso or jb and then bore scope. Solvents will not remove hard carbon.

Not really. The metal is a little shiny, but I normally only 'scope it *after* cleaning... and yes, I'm using JB, as mentioned above, because the other stuff wasn't touching it.

I'll try to get some pics uploaded sometime today. As you say, the Lyman isn't exactly the highest optical quality... but I can only imagine this would look *worse* in a Hawkeye.

 

[msinc]

.......The amount of coppering was roughly correlated to the barrel life i.e. the more rounds, the more fouling.
........... JB Bore Paste... which did a *much* better, but not complete, job of getting the black nasty out. Still had a few long copper streaks in places, though..........

I am not too sure what you got going on here...a few things don't seem to add up. More rounds typically equals less fouling over time, that is to say the more you shoot a given barrel the less it should foul, per se. But, then again, the more you shoot the more copper can get in the bore...I don't know how many rounds you typically put thru this thing at a time.
I have seen some bad copper in bores that "took a little doing" to get out, but JB should be getting it out of there in two or three applications. With that, the black stripe is usually gone before the copper. I don't know what that black stripe is, and with my rifles when I see it it is always in only one of my guns. There is another that does it a little, but the one barrel is bad for it. I use the same powder and bullets in others so I cant tie it to ammo. The barrel I have that does it is a factory Remington on a 700, but to scope it it looks like the interior finish could rival any custom made...once in a while you get one from the factory that looks really good, and this one's it.
When I have copper that takes more than one application of JB to remove it the end result is a whistle clean and "white" bore. By white I mean if it is a blued rifle the bore is now looking like new stainless, if it's stainless then it looks like it has never been fired and the black stuff always comes out before the copper.
Can you tell us what caliber and type of barrel this is??? By chance is this thing a semi??? Maybe I missed it, but I don't remember reading exactly what you are shooting here. I will add that my barrels seem to stay cooler longer with VV powders. How hot does this barrel get when you are shooting???

 

[Richard Coody]

I had the beginings of hard carbon in the throat and continuing up the lands. This is what worked for me. Everything i did was from suggestions on this forum.

Get you a parker hale jag. It is long and will hold a large patch wrapped around it better than anything i have found. It is brass so if you use it with a copper remover you will see the blue. We are really just going after carbon here though.

Use your favorite cleaner and either losso or jb on the patch and short stroke the throat and ten or 12 inches up the bore. I also would soak a patch and let it sit in the problem area. You will be shocked by the crude that is going to come out of what you thought was a clean barrel


Now boretech C4 will keep it under control. That stuff is amazing. Found it after my bore scrubbing.

This will let you know if you have a.carbon problem or it is actual barrel erosion.

 

[Jet]

I've tested just about every commercial carbon and copper cleaner that is out there in a quest to find what works best. Like you have seen my observations don't support most of the claims made about many of the popular products (use a Hawkeye to verify). Like recommended above IOSSO or JB will get the job done. I'll clean the soft carbon with Hoppe's Elite or M-Pro bore gel then look down it with the scope. If needed I'll use IOSSO to get out the tough carbon or copper. Always works but I've never let it build up heavy.

Good Shooting

Rich

 

[memilanuk]

So, for reference, here are a few pics of what I'm talking about.



This first one is from a factory .308 bolt gun, so yes, it's a bit rough You can see one land there at the bottom, then some residual tool marks that were hidden/protected under some carbon build-up against the land, a big wide shiny groove, then the beginning of the same carbon and tool marks at the top, adjacent to the next land (not visible in this view). The relevant bit is the 'big wide shiny groove', i.e. what I would expect to see. Barrel has approx. 2500rds through it, mostly 155 and 175 gn bullets (some 168s) at moderate speeds. The primary erosion is along the lands, not the groove.




Here we see some of what I've been trying to describe. Land at the top, land at the bottom. Shiny metal on both *sides* of the groove, with nasty char / erosion in a strip down the center of the groove. Bear in mind, this is *after* a fairly thorough cleaning with carbon and powder solvents, then 20 strokes with a tight-fitting felt lap (the VFG pellets mentioned earlier) soaked in Kroil and loaded with JB Bore Paste, then flushed with solvent and patched dry. I don't recall which barrel I took this picture from, or what the exact round count was - but if its the one I think it is, probably around 2500rds - all 200 Hybrids, with Varget, running ~2700fps (.308 Win). F/TR, single load, 'slow' fire... though the barrel has certainly gotten toasty a few times - the nature of the sport and the conditions its shot under.

For those of you who think this is just a carbon glaze, I disagree. I realize that the Lyman borescope doesn't exactly take HD pics, but I'm reasonably certain that the metal there is *gone*.






To illustrate what I mean when I say I don't think its a carbon glaze, here is a pic of the inside of my .30 BR Varmint-For-Score barrel. Probably about 600-700 rds through it. You can see the land at the top, a bright shiny strip at the edge of the groove, and some shiny black/grey carbon fouling with a hint of heat checking underneath. This barrel runs a custom 112gn FB at a little over 3000 fps.

Hopefully this clarifies what I'm was trying to say before. Yes, I have tried abrasive cleaners like Witch's Brew and JB Bore Paste - as was stated in my second post. No, it doesn't look like something a simple scrubbing will cure. And yes, I am very, very curious as to just WTF is causing these barrel(s) to erode the *grooves* like this. I've got a couple new(er) barrels, different brands, similar bullets (200.20X vs 200 Hybrid), different speeds, one @ ~200rds, one @ ~850 rds, both exhibiting the same symptoms, just not as deep/long of strips - yet.

 

[DaveTooley]

Just a bit of information based on my observations. Bullets contact the barrel on top of the lands, about 40% of the center of the groove and the base upsets to seal off gases. At least that's what recovered bullets show. Overlay that contact patch in the barrel and it explains a lot of what you are seeing. Contact means friction which creates heat which shows up as heat checking.

 

[coford]

Monte,

I get the same thing in my .284's. It usually extends to about the middle of my barrel (32"). I can get it out by using Iosso paste and a little scrubbing. It also shows up in my Dasher. I have made it a regular practice to clean it thoroughly about every 200 rounds and it seems to keep it at bay. Once removed the groove shines again. When my .284's are really dirty I also see the black on to of the land in the middle section - it also scrubs off.

 

[AckleymanII]

I have seen this a lot, and it comes from a cleaning technique that is inadequate.

Montana Extreme Copper Cream(it is like JB or ISSO suspended in Oil) on their plastic brush will get rid of this problem, post haste!

Now that you have a Lyman bore scope, you can monitor your cleaning and the build up will not happen. When you get behind the 8 ball, it is a bitch to get that carbon out.

I will send you a PM