Borescopes

[mtngun]

When evaluating high velocity cast loads, I often found myself thinking "I can't see any fouling with my naked eye ....... but I don't really trust my naked eye."

Plus now that I am learning to make my own reamers and chamber barrels, I often wish I could examine the throat to make sure it cut nicely.

The popular Hawkeye borescope is way out of my league, pricewise.

But I found a used Russian scope on ebay for $60. Lacking anything to compare it to, I can't comment on the quality of the Russian borescope other than to say that it does work satisfactorily. My only complain is that the tubes are bigger than the Hawkeye, 0.284" with the right angle attachment, effectively limiting it to 30 caliber and up.


I recently learned that Lyman is introducing a It can measure down to 22 caliber plus take pictures, too. I wouldn't mind having one of those so I could post pictures of my barrel condition.

[mtngun]

Link to

[mtngun]

Here's a Chinese

I haven't tried it, and I'm sure the rule about "you get what you pay for" applies, but if it actually works to a usable degree, it might be worth having.

Update: someone advised me that the focal range on the Chinese endoscopes is about 2", and that the right angle attachment is useless in a gun barrel because the barrel is too close to focus.

[mtngun]

While my Russian borescope works well enough, it only fits in 30 caliber and above. Well, that certainly seemed like a good excuse to pick up a Lyman borecam, right ?

Here are some borecam pics. the one bad thing is that photo resolution is limited to 320 x 240 pixels, so the photos will never be great quality. The resolution does appear sharper and brighter on the borecam screen than in the photos, though, and it's quite adequate for detecting fouling, pitting, etc., so the bottom line is that it gets the job done.

X-Caliber 224 barrel. I paid $140 to my door for this blank and it looks perfect !


Shaw 30 caliber barrel. Looks like it was machined with a chainsaw -- and this is AFTER it was firelapped! The bore had a reverse taper, too! This was my first and last Shaw barrel.


Remington 270 barrel. Some stretches of the barrel had a surprising amount of chatter, while other stretches were OK. You can't tell in this photo, but the streak above the chatter is copper fouling.


Ruger Speed Six 357 barrel, near the muzzle. Most of this barrel looked smooth but there was some light chatter and fouling near the muzzle. I haven't cleaned it in ages. BTW, I blew up this photo to 600 pixels wide, but I wasn't able to make it any clearer, so in the future I'll stick with the 320 pixel photos.


So mostly I am happy with the Lyman bore cam. One thing I did learn very quickly is that the tip picks up dust easily, and because there is so much magnification, even a little bit of dust shows up as big blobs and reflections on the screen. The q-tips that Lyman supplies are a little too big to reach all the way in, so I'll have to figure out a better cleaning technique.

[mtngun]

Another minor quibble with the Lyman bore cam -- it assigns the same wrong date and time to all photos on the disk -- Tuesday, August 1, 2000, 1:53:52. Would it be that hard to assign a proper timestamp?

Anyway, here are some more borecam photos. First up, a Pac-Nor 7mm barrel blank that hasn't been shot yet. This barrel was not purchased from Pac-Nor but rather from ebay as some sort of close-out or overstock, so it's possible that it is a factory second. Normally Pac-Nor barrels are lapped at the factory. This one looks pretty smooth though not 100% perfect.


This is another close-out Pac-Nor that hasn't been shot yet, this time a 6mm 3-groove. Like the previous Pac-Nor it looks pretty smooth though not perfect.


This is a Shilen 6mm blank that hasn't been shot yet. This is their $140 econo-grade barrel that is *not* lapped. There was some very faint chatter in a few places -- the photo shows the worst of it. Most of the rest of the barrel was smooth. I'll probably lightly firelap this barrel as I have done to my other Shilen barrels (by lightly I mean only 5 - 10 rounds of firelapping).


Of all the barrels I have examined so far, the X-caliber has looked the best, the Pac-Nor's 2nd best, and the Shilen 3rd best. I'll examine more barrels as time allows. In the meantime I wouldn't hesitate to buy another X-caliber, based on how it looks, anyway.

[mtngun]

Here's a used Remington 30-06 barrel. Besides the obvious copper fouling, it looked decent, with no major roughness.


Here's my Marlin 357, which has been both hand-lapped and firelapped. There was no chatter to be seen, but nonetheless a few light streaks of lead on the muzzle end. The last few shots in this barrel may have been plain base for water tank tests, so that may explain the leading. Normally I shoot gas check bullets in the Marlin.


The Marlin 357 again, with significant pitting on the breach end.


Marlin 357 with pitting about one inch ahead of the chamber. I presume the pitting is due to powder/heat erosion and roughly corresponds to the point of peak pressure. The pitting occured in patches, some patches were highly pitted while the area right next to it might be unharmed. Weird.

[mtngun]

Here's my Contender Green Mountain 357. This barrel has been firelapped extensively.

It mostly looks smooth -- not match quality, but quite decent and free of chatter. However, as I noted several months ago, there is light pitting here and there. This one was near the throat.


But this one was much further down the barrel. I don't know what causes the pitting, but some of them look like corrosion. Since I noticed it several months ago I began giving the barrel a good solvent clean at the end of every shooting session, whereas before I rarely bothered to clean it because I assumed the residual bullet lube would protect from corrosion. So at least until I get this pitting figured out, my standard procedure for all guns will be to clean at the end of the shooting session.


Here is a Shilen standard grade 30 cal that I've chambered for 30-06 but haven't fired yet other than 5 firelapping rounds. There was light chatter all the way through it, this was the very worst spot. After looking at this I may opt for a few more firelapping rounds.

[mtngun]

The Shilen barrel on my Contender 6x45. This is the econo-Shilen not the fancy grade. It has received 10 firelapping rounds. This was the worst chatter I found, and only in a few spots, most of the barrel is smooth and fouling has not been an issue.

[mtngun]

A Green Mountain 10/22 barrel. Mostly smooth, but not perfect, with a wee bit of fouling here and there. I don't recall whether I ever firelapped this barrel but it might benefit from a few firelapping rounds.

[mtngun]

A Brazilian clone of the Remington 511 22LR that I bought at Wally World 20 or so years ago. Out of the box, bullets would not stay on the target backer and when they did hit, they hit sideways. Turned out the chamber was off-center so much you could see it with the naked eye. I set the barrel back back and rechambered by hand with a bentz reamer, then it shot 1 1/4" - 1 1/2" 5-shot groups at 50 yards if I remember correctly.

Despite the bentz chamber, I think this is a candidate for a new barrel, eh ? Holy crap, Batman !