Undeniable Borescope diagnosis

[Bartojc]

You can get clean patches and still have hard carbon laid down in the bore.

Almost guaranteed if you don’t have a scope to see it. I used to think I did a really decent job cleaning rifles until I bought the Teslong. Not sure it’s an issue but my barrels are not perfectly clean, far from it.

Jeff

 

[SwampWolf]

Ignorance is bliss.

 

[lysanderxiii]

My personal opinion: a borescope is only useful for people that cannot shoot worth a hoot and need an excuse for why their rifles group poorly.

The primary technical use for them is to monitor quality in production, and record the progress of wear, but NOT when a barrel is "worn-out", that is more easily established by monitoring the group sizes over time.

 

[lysanderxiii]

I've had my first borescope for a month or two now, and you may be right - I'll probably never use it to diagnose trouble, but I HAVE already used it to tell me when I'm done cleaning; no longer will I go by that old (and indirect) advice "when the patch comes out clean". Now I can clean until the bore is clean.

I can't agree with your position that they're not justifiable, not when a good one is available on Amazon for $40. At the very least, pictures of a clean bore lend credibility, and may even increase the final price, when you post a gun to an auction site. It seems to have worked for me lately. Possibly it paid for itself.

I am waiting for the day an Inspecting Officer whips one out during the final inspection at MCRD . . . .

 

[RavenTai]

There is truth here, I got a teslong about a year ago, great inexpensive bore scope.

But

when you pipe it through your computer to the 65" TV tiny machine marks become the grand canyon, dust become bolders, the smallest bit of rust becomes a huge malignant tumor, and cleaning takes 3 times longer. Even though I know better when you see it, you feel you have to think about it.


The worst barrel I have seen yet was my daughters savage rascal, horrible machine marks that completely interrupt the rifling. My son has one made a few years earlier that has a great bore.

Both shoot the same.

The problem with bore scopes is that you see things that most people don't need to, or shouldn't see. Like tool marks or a trace of copper fouling. So all of a sudden, a perfectly good shooting rifle suddenly becomes defective.

I'm starting to believe that cleaning often doesn't improve accuracy. At least in my rifles. Once every 250-300 rounds or at the end of the season is plenty. You can "read" your patches to determine where you are in the cleaning process. You don't need a borescope.

But the $50 Teslongs are inviting. Just beware of what you're going to see!

 

[Nature Boy]

My personal opinion: a borescope is only useful for people that cannot shoot worth a hoot and need an excuse for why their rifles group poorly.

I get that's your opinion, but what's the basis for it?

 

[jmorris]

My personal opinion: a borescope is only useful for people that cannot shoot worth a hoot and need an excuse for why their rifles group poorly.

Same as those quack "Doctors" that want to rely on tools like X-rays, CT scans or MRI's, to see things that can't be seen from the outside.

 

[Ivy Mike]

I tend to think of this in terms of the barrel being a bit like a piston and cylinder in a car's engine. You know that with every up and down stroke, a tiny amount of wear occurs. This is just a fact of life when you use the engine. Same with the barrel of any gun. Every time you pull the trigger, wear occurs. What I think happens is that someone has been shooting the weapon for a long time and notices that it's no longer shooting very well. To them, it appears that a problem has occurred when in reality, they've put 11ty thousand rounds down range with only their claims of having thoroughly cleaned the bore. Every time they just give it a quicky cleaning, some of the nice hard carbon breaks loose and gets raked down the barrel with the bullet coming by and scratches the bore. It might be microscopic but it happens and wears the bore a little more.
The process has occurred long term and they've simply been compensating and not keeping accurate records of the zero of the rifle. In a car, you haven't been letting it warm up and circulate oil before driving. You might have been lax in your oil change regimen. You never bothered changing the shocks and now can't understand why the car is eating tires.
Same thing with a rifle. It's now shooting poorly because it's just worn out, either from regular use and/or irregular maintenance. Metal parts subject to friction and heat, wear out.

A bore scope is useful if you're going to be on top of your rifle. For a competitive shooter who does their own work and is keep accurate records, it might make sense. You could likely save a fair amount of money over the years when it comes to keeping match grade barrels in service longer by scoping them and being more thorough in cleaning and polishing.
For your average shooter who goes hunting once a year or once every couple of years, you won't see much difference. It's a neat toy, nothing more.

I love finding new uses for other products and figuring out what products are snake oil and which aren't. Instead of buying a borescope to find the carbon you think might be fouling up your rifling, take the rifle out of the stock, bring your grill up to 200 degrees for a little bit, buy a $5 can of oven cleaner and coat the inside of the barrel and chamber. Stick the rifle in the grill, kill the heat and wait 10 minutes. Give the barrel a good cleaning and be amazed at how well it cleans up. Will you know that your barrel is sparkly clean or how the minute scratches inside look?
No. But you will have done a very thorough cleaning on it and removed all sorts of carbon fouling and schmoo you couldn't get before. We used to do that on the old EGR valves from VW diesel engines. $5 can of engine cleaner and some heat could save you hundreds of dollars on EGR repairs.

 

[lysanderxiii]

I get that's your opinion, but what's the basis for it?

The number of time I have seen or heard of someone pointing out the most inconsequential manufacturing feature or anomaly seen in a borescope picture, and asking if that could affect the accuracy, quite often, gas port erosion.

And, like those X-ray and MRI machines, they can be quite useful if you know what you're looking at. But, most people with borescopes don't.

 

[Nature Boy]

Same as those quack "Doctors" that want to rely on tools like X-rays, CT scans or MRI's, to see things that can't be seen from the outside.

these dang whippersnappers and their new fangled gizmos!

 

[Walkalong]

Since I have started looking at barrels with a borescope I am learning something completely new to me, and that is how what I see actually matters. It will take a while to know.
My buddy that asked me to look at his barrel asked me what we saw meant. I told him the truth, I don’t know yet, all I can do now is note the condition and watch how it progresses and how accuracy is affected. My 6 Dasher barrel shot a .458 and a .280 group yesterday checking velocities with a new lot of powder and a new scale. I know what it looks like inside, so that is knowledge gained.

 

[jmorris]

And, like those X-ray and MRI machines, they can be quite useful if you know what you're looking at. But, most people with borescopes don't.

Lots of people can't paint a work of art but that's not the pait brushes fault or make it any less useful in someone's hands thay can utilize it to it's full potential.

 

[RetiredUSNChief]

Haven't used a borescope on firearms, but I have used them at work a few times, with great success.

Had a piece of equipment on one of the carriers in the shipyard which was having problems that indicated an obstructed pipe/valve. Scoped out the piping OK, found the problem with the solenoid operated valves, and fixed it.

Scoped out a piece of conduit on a submarine and discovered a wad of EB Red tape stuck half way down the conduit, preventing us from pulling a cable through. Had to cut the conduit to remove the section with the tape and splice in another one.

Had some missing hardware on a reactor coolant pump breaker. Before replacing it, used a borescope to conduct a thorough inspection of all the interior spaces of the breaker to ensure there were no metallic pieces adrift inside. fun times!

 

[film495]

I've thought about getitng one, but realize I'd have little/no idea what I'm looking at. If they shoot OK, figure that's good enough. When cleaning, my experience says you can often feel build up with a bronze brush, and then also with a patch, so - that little hiccup or grainy feeling when pushing through indicates cleaning is not finished yet. That part is mostly about feel, smooth is smooth, not smooth means something is in there.

 

[Varminterror]

Lots of people can't paint a work of art but that's not the pait brushes fault or make it any less useful in someone's hands thay can utilize it to it's full potential.

This is one of the motivations for my question in this thread:

I’ve used borescopes for years, and have seen them used by gunsmiths for even longer, but I can’t be sure I have ever seen the “work of art” which can be done with a borescope, so I’m undecided whether I know the “full potential” of the tool.

If the full potential of a borescope is determining whether a bore is truly clean, or diagnosing carbon rings, ok. If the full potential is to scare customers into buying a new barrel, ok. But I sure wish the information found when dipping a bore were more valuable than I have been able to make of it.

 

[SGW Gunsmith]

I have and use the Lyman bore scope, not every day, but often enough and will not provide an apology for that purchase. I do the deciding for what devices I choose to purchase, and no one else. I actually like to learn about what a cut-rifled bore looks like, same as a button rifled or hammer forged barrel's bore, or in bores with multi-groove rifling. I like to see, for myself, if the chamber and leade cutting reamer left a sharp burr on the trailing edge of the lands, due to the reamer getting dull.
I'm curious about these things and sometimes have gone to lengths to actually see the rifling depth in an old .22 rimfire barrel:

Personal opinions concerning ownership and use of a bore scope are just that, personal opinions, but they have nothing to do with someone else's personal choices, which should be left up to the individual.

 

[Bfh_auto]

My personal opinion: a borescope is only useful for people that cannot shoot worth a hoot and need an excuse for why their rifles group poorly.

The primary technical use for them is to monitor quality in production, and record the progress of wear, but NOT when a barrel is "worn-out", that is more easily established by monitoring the group sizes over time.

Or it can show you that a "terrible" barrel can shoot well.
I'm getting one because I have a rifle that was so bad you couldn't see the rifling.
After soaking, brushing, soaking and patching. It still was bad. I ran some cast bullets with valve grinding compound on it.
It now shoots well without leading.
I'm curious what it looks like.

 

[Demi-human]

For the fifty dollars, the Teslong answered a curiosity of mine.

Even though it looks like railroad tracks, my Savage shoots very well. Looks the worst, shoots the best, doesn’t even really copper.
A VDI AR barrel of mine is wonderfully smooth and shoots well for it. And I wish I hadn’t shot it smoking hot so often and fire checked it so badly in the throat, and strangely to me, after the gas port.(Turbulence.) Despite slight neglect, and high round count, there were no copper deposits, none.

But, as far as a problem with the bore, just by looking at with a bore scope, nothing else, I don’t think it’s all that useful. It is interesting, but without other tools is nearly useless.
It can tell if a bore is clean. But so can a patch.
It can tell if there is hard carbon, but so can a target and a bullet shank.
It can show wear, but not if that wear is detrimental.

Everything else can be measured or seen with the naked eye, leading, worn out rifling, corrosion. Indeed, without a target of some sort missed why would we be looking?

It can’t tell you the twist, or if your bullets fit properly, or if those few rust pits from last years rain hunt really hurt any.

Even though I haven’t gotten a chance to use it on any reactors yet, I like it. The paltry outlay is worth the satisfaction of my curiosity. The Lyman, or especially the $1500 Hawkeye? Ridiculous. Completely unnecessary, from a consumer aspect.

Say there is some defect that we can deliberately see. What could a consumer do about it?
Pound a rifling button through with a brass rod?

I admit when I got it all set up and saw this, I was concerned.

Or this, a chunk of bent back into place steel.

But then I felt silly, because it still shoots great. What did I think I was going to see?
It isn’t useless, but it’s is talked up a bunch.

 

[SGW Gunsmith]

Well, with the Teslong scope, not using a shaft and only a cable, you could also do your own colonoscopy checks. My Lyman with its shaft might be an issue concerning that attempt.

I still gotta wonder, though, why some folks who find that they have a sorta rough bore, or a bore not to their liking, will go through the efforts of "fire-lapping" said bore. If shooting doesn't improve, sounds like a wasted effort.

 

[RetiredUSNChief]

I'm willing to bet that rifle bores, not being cut and polished like they're some kind of jewelry product, are going to exhibit a lot of "imperfections" and "blemishes" when scoped out that a lot of inexperienced people aren't going to be able to properly evaluate.

A visible blemish or imperfection when seen waaaaaay up close does not automatically translate into unacceptable performance under use.

As an engineer, I've had occasion when getting into the deep nuts-and-bolts of some of my instrumentation and control equipment to the point where we're actually considering really tiny issues. And the question that has to be answered is "what's the spec?"

Often times there may be no spec, simply because such matters weren't considered when the device was designed and built. Then it becomes something to be evaluated based on a variety of issues. These issues may involved inspecting the same, or similar, equipment used elsewhere, spares in the supply system, wear characteristics on the equipment, how such blemishes and imperfections may or may not actually affect the equipment, the materials used in the equipment, the manufacturing techniques in the machine's construction, etc.

For a rifle, the bottom line boils down to a couple factors:

1. Does it affect the ballistics?

2. Does it affect safety?

So...how would something affect ballistics?

Seems to me that this depends on the location of the defect and the precise nature of the defect.

A mild defect located relatively far from the barrel muzzle might not have any noticeable affect at all, so long as it didn't cause a permanent deformation of the bullet, shave excess material off one side as the bullet passed over the defect, or otherwise affect the geometry and mass distribution of the bullet as it passed over the blemish and down the barrel. The rest of the barrel might serve as a "corrective force" for any minor issues caused by the blemish.

A mild defect at the crown of the barrel, however, could have a much greater effect on ballistics. This is because there is no more barrel left to correct any minor bullet deformations.

Defects which contribute to barrel fouling in certain parts might contribute to poorer performance after a period of some use...or, on the flip side, might contribute to better performance after a period of use.

Bottom line is that if the gun is otherwise performing as it should, you shouldn't be too concerned about what minor imperfections you may find in the barrel, as they obviously aren't having a noticeable effect on performance.

However, if you ARE having performance issues with the firearm, then scoping MAY reveal the cause, but likely ONLY if you know what you're looking for.

 

[SGW Gunsmith]

When I actually worked full time in a "prototype toolroom" we did a whole lot of Government procurement work. If it didn't make contract specification, it didn't get the government inspectors stamp so it could ship.
In my current profession I work most often with .22 rimfire barrels, so I do cater to smoother bores due to the softer lead bullets spun through rifling that's only 0.0020 to 0.0025 thousandths of an inch higher than bore diameter. So, my curiosity involves how the bores treat those .22 Long Rifle bullets as they travel through that rifled pipe.
Being that a carbide "button" gets pulled through most of the .22 rimfire bores, or they may get hammer forged, I like to see how that process turned out. But to actually try to find open and tight spots in a .22 rimfire bore, my best luck involves slugging the bore to feel how that slug moves through. From what I've noticed is, that a .22 rimfire bullet that is the same diameter of the bore, or maybe 0.0005 larger, will shoot much more accurately than an undersize bullet.
I know, chasing this issue is sometimes like trying to catch a fart in a bottle, but it keeps me out of the local saloons.

 

[Walkalong]

You can feel the difference in a true match grade barrel vs most factory barrels when you run patches through prior to shooting and then cleaning.

You can see it with a bore scope as well.

 

[Bfh_auto]

Polling the peanut gallery for experiences here...

What problems have you undeniably and by no other means identified and been able to solve because of a bore scope?

The common context: a rifle which shot well, no longer will. Guys run a borescope and see copper fouling or a washed leade, and recommend pushing out copper or replacing the barrel, respectively. In the former case, maybe things improve, maybe not. In the latter, assuredly things change, but it doesn’t particularly satisfy that excessive throat erosion is proof the barrel can no longer shoot well.

Note - I am not asking for a report of what “ugly things” you’ve seen in a bore when scoping a rifle with an otherwise unidentified issue. We all know when you run a borescope into a bore, you’ll see anything and everything from carbon or copper fouling, rings in the barrel, fire cracking, “grease slicks” of copper streaks, washed lands, chatter, pitting, etc. However, my challenge is that I have rarely found a significant and undeniable correlation between these commonly observed “defects” and performance on target.

I’ll go first: the only issue I can say after 20+ years of owning and regularly using borescopes that I can definitely identify, diagnose, and confirm as resolved with no other means than a borescope has been a carbon ring in the chamber.

Do you think this might be the cause of not getting better than 1 1/2" groups?
It circles the entire bore about half an inch from the muzzle.

 

[Varminterror]

Do you think this might be the cause of not getting better than 1 1/2" groups?
It circles the entire bore about half an inch from the muzzle.

This is an example of what I’m talking about in creating this thread: the only way to decide if this particular “ugly” anomaly is the culprit behind your accuracy woes would be to remove it somehow. Cutting 1/2” off of the muzzle end and recrowning would be a multivariate change, so even then it could be written off as speculation if it shot better after - but I’d tend to expect eliminating THIS bit of “ugly” would be more influential than 1/2” of length and a new, similar crown. But without cutting the barrel down, it’s only speculation to say this ring is problematic.

 

[herrwalther]

I'm willing to bet that rifle bores, not being cut and polished like they're some kind of jewelry product, are going to exhibit a lot of "imperfections" and "blemishes" when scoped out that a lot of inexperienced people aren't going to be able to properly evaluate.

I have had customers call me asking to borescope their barrel. My first question is always how does it shoot? Because if it shoots fine there usually isn't a reason to borescope looking for a problem that isn't there. But some customers are just curious to see how well they can clean a barrel.