another use for the borescope - seating bullets to the lands
From James Tate at Nationalmatch.us


Accurately measuring bullet contact with the lands for calculating jump has always been a problem for me. I was able to use the borescope to tell when an SMK 80 is touching the lands.

1) Insert borescope, without mirror, into the barrel from the crown end.

2) Insert bullet held by the Hornady OAL gauge.

3) Carefully slide the borescope until you can see the bullet. It needs to be clear enough to detect bullet rotation.

4) Gently push the bullet into the lands until you feel contact.

5) Watching through the borescope, rotate the OAL gauge. The bullet should rotate with the OAL gauge. If not, back out the bullet until it does.

6) Gently push the bullet in. Look for rotation. Push in gently until rotation stops.

7) Remove the bullet. If you are just touching the lands the bullet should come out without any force.

8 ) Measure the OAL.

In the one try I could see that at 2.495 the 80 SMK rotated. At 2.497 it would not rotate but easily came out with the OAL tool. At 2.500 the bullet was jammed and had to be pushed out.

This video is large but should stream easily. Not much to see but interesting. The first 10 seconds the bullet is seated at 2.495. You can see the bullet rotate freely when I rotate the COL tool. Second half, I adjusted the COL tool in and now the bullet will not rotate freely but you can see the bullet move as I rotate the OAL tool. Bullet did stay in the COL tool on extraction. This measured 2.497. Not in the video is the last step I made by pushing the bullet hard into the lands. That measured 2.450 on extraction. Extraction required a push from a cleaning rod.

In this case I would use 2.497 as the starting point to calculate any jump.

https://drive.google.com/open?id=1TvtAAU_jzfIZEdqBpeobnZwYtALhDBXC

Ren,

You started this conversation..........   

Don't you want one?    Don't you need one ?

Ren,

You started this conversation..........   

Don't you want one?    Don't you need one ?

Contemplating one but I'm in a holding pattern as far as rifle shooting goes.
Working on interior plantation shutters, home improvement stuff got me occupied as well as work related mandatory stuff....

Anybody bought one?

Tell me how you like it...............

I have it. Pretty damn impressive after tinkering with the focus and the lighting. Each caliber will need different 'settings' i did .223 6.5 and .308 so far.
I bought it to check for pitting and mostly to see gas block port alignment. The angle of the light doesnt really reach down into the gas port but its just enough to confirm its aligned. It focuses no problem but its dark.

Major con is just like a lot of decent chinese sensor electronics it runs off of a buggy app.  In fact i blame the app for completely bricking my galaxy s9. It happened the same night few hours after installing. Id post the pretty clear shots i got of the 3 barrels i used it on before it crashed but all my photos not saved to sd card are gone for now  . Im afraid of downloading the app to my only working smartphone i have left. I may try it again after black friday, if i find a good deal. Otherwise gonna wait til galaxy 11 in feb. I dont want to download to my tablet or pc. Before the black screen of death the app would get blocky n freeze after about 1-2 minutes of borescope use.

Anybody bought one?

Tell me how you like it...............

I have it. Pretty damn impressive after tinkering with the focus and the lighting. Each caliber will need different 'settings' i did .223 6.5 and .308 so far.
I bought it to check for pitting and mostly to see gas block port alignment. The angle of the light doesnt really reach down into the gas port but its just enough to confirm its aligned. It focuses no problem but its dark.

Major con is just like a lot of decent chinese sensor electronics it runs off of a buggy app.  In fact i blame the app for completely bricking my galaxy s9. It happened the same night few hours after installing. Id post the pretty clear shots i got of the 3 barrels i used it on before it crashed but all my photos not saved to sd card are gone for now  . Im afraid of downloading the app to my only working smartphone i have left. I may try it again after black friday, if i find a good deal. Otherwise gonna wait til galaxy 11 in feb. I dont want to download to my tablet or pc. Before the black screen of death the app would get blocky n freeze after about 1-2 minutes of borescope use.

Wow, your experience is not too good yeah.........
I downloaded it to a large laptop, as I want to see a large picture. 
It worked as advertised... only thing is that there are white dust paticles on the lens or mirror which make it look messy....

version 2 is out
https://www.amazon.com/dp/B081T1DN1P/?tag=accuratescom-20

Well i cant be certain it was the app, the phone was over a year old i guess. It took clear enough pics for me to try again. I have a backup phone to try it on now.
I just ordered the gen2 straight rod. I returned the flexible one. Ill report back if its any better.

 

Wow, your experience is not too good yeah.........
I downloaded it to a large laptop, as I want to see a large picture. 
It worked as advertised... only thing is that there are white dust paticles on the lens or mirror which make it look messy....

I would restore your phone to factory settings and clear all data.  Then just load that app and see if it happens again.

I would be interested but there is no iPhone/iPad version. Unless I missed something?

Just got mine today. This tool is awesome!
Hooked it up to my Mac and used Photo Booth. No need to install any other apps. Scoped all my barrels. This pic is of my Shilen barreled SR upper. Gas port

Tempted also.

So if my barrel does look like this but I'm getting 0.3 moa, what does it mean?

Firecracking. usually happens near the throat as the barrel wears

Thats a pretty damn nice image. May have to get 1 since its cheap.

I have a borescope (3 or 4 yrs old) but i had it for automotive purposes. Mines costed 200 or so. Its a handheld unit, but it saves pics and i think 10 sec video to a sd card. Pics i know for sure.

But i did use it to check gas port alignment. After noticing my case wasnt ejecting. Proved pretty damn useful. I just made the hole bigger on the gas block.

Cool beans!  And, there is a 10% off coupon right so it is only 45.00 plus usary.  Free shipping.

Got mine couple days ago. 

Had my RWS 48 air rifle out so used it on that.  Immediately saw some lead deposits in the bore, did not think pellets leaded airgun bores, but now i know.

had one few years back the resolution is not soo good

Not figured out yet if this can grab a single image, or you are forced to mess with a video stream.

Do not want a video travelog, just want snapshots to examine and compare.

Ah, belay that, found the second program that does the single shots.  Their blurb only seemed to mention the video capture.

pics of the leade in a Faxon barrel. Not good.

How are you setting the illumination dial?  I find it too bright and cannot hold it at a low setting.

Got to wonder how much the tooling marks will affect anything right at the throat.  Does look like the rifling starts at different spots, not the best machining or tools/

the illumination dial is pretty sensitive on mine. If I remember I set it at the lowest setting