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New flexible borescope


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5 hours ago, baldie said:

Nothing to do with not using a bore guide Dave. You wouldn't wear two lands away by cleaning, if you did it every day.

The lands have worn/dissapeared, because it highly likely its a Hammer forged barrel. Especially the chrome moly ones, are very hard, but very brittle. pieces simply fly off.

Saw it on a TRG .338 not long back. Lowish round count, and six inch of one land, completely missing.

Thanks Dave,,,,,just took a couple of pics for  interest,,,,this rifle does not get the love and attention of others in the cabinet and i must take more control of my carbon I reckon!!damn thing is accurate though,,,,,,,!,,,,,,,O

Snap_009.jpg

Snap_011.jpg

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A picture tells a thousand words.....

A most un-concentric chamber. Can't say why that land has worn like it has, but looking at that leade, it could be putting undue pressure on one or more of them.

bet it still shoots however.

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I had the option to start a temp job as a gunfitter for work experience, or wait 3 or 4 months, for my main job when I first started working as a contractor to the MOD in instrumentation/photography/radiography field. While working in said temp job I can remember looking at various barrels using borescopes.

Boy was it a wake-up call. Gas-washing, heat-cracking, chrome plating delamination and stripping, ripped off lands due to things coming off projectiles as they were fired. These were big guns, tank and artillery pieces.

I can remember one of the scientists telling me heat-cracking, often combined with chemical attack by the propellant decomposition gases due to the high temperatures and pressure, can result is cracks forming that travel into the main body of the barrel. This can result in barrel failure even though the pressure was never enough to cause a fatigue life failure due to repeated pressurisation, ie firing it.

Fatigue failure is a failure due repeated loading past a material's fatigue limit, below that limit you 'should' be able to cycle it repeatedly for ever. I think Ive seen one example of a hunting rifle blowing up of which this was effect was the probable cause.

 

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54 minutes ago, BlueBoy69 said:

I had the option to start a temp job as a gunfitter for work experience, or wait 3 or 4 months, for my main job when I first started working as a contractor to the MOD in instrumentation/photography/radiography field. While working in said temp job I can remember looking at various barrels using borescopes.

Boy was it a wake-up call. Gas-washing, heat-cracking, chrome plating delamination and stripping, ripped off lands due to things coming off projectiles as they were fired. These were big guns, tank and artillery pieces.

I can remember one of the scientists telling me heat-cracking, often combined with chemical attack by the propellant decomposition gases due to the high temperatures and pressure, can result is cracks forming that travel into the main body of the barrel. This can result in barrel failure even though the pressure was never enough to cause a fatigue life failure due to repeated pressurisation, ie firing it.

Fatigue failure is a failure due repeated loading past a material's fatigue limit, below that limit you 'should' be able to cycle it repeatedly for ever. I think Ive seen one example of a hunting rifle blowing up of which this was effect was the probable cause.

 

Scary!! Hope I don,t develop a flinch after reading this,,,,Ha?

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12 hours ago, onehole said:

Scary!! Hope I don,t develop a flinch after reading this,,,,Ha?

I shouldn't worry, I don't think it's a very common occurrence with small arms, or even the big guns. If I remember rightly the gun had fired a few 10s of thousands of factory rounds 30-06 power level ammo over its rather long life as a hunting rifle. They fired a round one day and the barrel split.

The only time I saw a big guns blow up was due to bore prematures. This occurs with high explosive projectiles when the fuze fails for whatever reason, or the high explosive has flaws in it (cracks/voids) which collapse under the acceleration of firing, setting it off. Whatever the reason, the shell goes off in the bore and there's not too much left around its burst point, or with the bigger guns, not much left of the barrel and sometimes the gun at all.

Going back the main subject... well sort of, you can even get optical and laser bore measurement systems for small arms now. I only saw them for bigger guns when I worked at the aforementioned place. Some info below.

https://www.novacam.com/barrel-inspection-and-3d-measurement/

http://www.laser-ndt.com/documents/LTC Product Sheets/Small Caliber Bore mapping systems.pdf

http://www.laser-ndt.com/defense.html

 

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53 minutes ago, BlueBoy69 said:

I shouldn't worry, I don't think it's a very common occurrence with small arms, or even the big guns. If I remember rightly the gun had fired a few 10s of thousands of factory rounds 30-06 power level ammo over its rather long life as a hunting rifle. They fired a round one day and the barrel split.

The only time I saw a big guns blow up was due to bore prematures. This occurs with high explosive projectiles when the fuze fails for whatever reason, or the high explosive has flaws in it (cracks/voids) which collapse under the acceleration of firing, setting it off. Whatever the reason, the shell goes off in the bore and there's not too much left around its burst point, or with the bigger guns, not much left of the barrel and sometimes the gun at all.

Going back the main subject... well sort of, you can even get optical and laser bore measurement systems for small arms now. I only saw them for bigger guns when I worked at the aforementioned place. Some info below.

https://www.novacam.com/barrel-inspection-and-3d-measurement/

http://www.laser-ndt.com/documents/LTC Product Sheets/Small Caliber Bore mapping systems.pdf

http://www.laser-ndt.com/defense.html

 

Wow, you've got to love 3D Laser mapping technology...…..I don't think we'll be seeing those on Amazon any time soon though :)

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