Borescope pics- anybody guess what this is?

[Dusty Stevens]

So the final answer is it is some kind of corrosion that resulted from the lack of proper cleaning?

Interesting question: Would the frequent use of a borescope have prevented this damage?

No a borescope has nothing to do with it. This particular guy doesnt own a cleaning rod. This is a kids hunting rifle. The frequent use of non moly bullets would have just left it dirty. The moly combined with humidity causes some kind of corrosion thats over my head but discovered many years ago

 

[skeeljc]

It has 14rds on it over 10 or so yrs and every single one was moly. It has never been cleaned and did not have this in there when new

Please explain "14rds" over 10 years? OOPS, I did not read the above post.

 

[tmwinds]

I am in Pipeline repair and that looks amazingly similar to the damage caused by an amoeba like organism found in gas wells. It will attach itself to the steel of the pipeline usually in areas where condensate collects. There it forms a colony like structure and actually feeds on the steel. The result is a leaking pipeline or possible rupture. Same kind of wormlike lines.

Exactly, in my 40 year career with a major petroleum company I have seen this type damage in the steel floors of petroleum storage tanks. It was more prevalent in diesel and kerosene tanks. It is actually a living organism that feeds on the metal. In large concentrations the living organisms looked like a jelly type slime. A preventative was to treat with a biocide and flush the bottoms of the tank. I'm not saying the damage in the barrel is the same but the appearance is similar.

 

[Dusty Stevens]

Please explain "14rds" over 10 years? OOPS, I did not read the above post.

In the 10yrs since i built it he has fired a total of 14rds

 

[Lefty Trigger]

I have seen that in the marine industry mostly on outboard motors, moisture tracks the grain structure in the metal. Some elements that make up the actual metal are more easily "eaten away" hence the weird track lines. We get people all the time asking why their $600 stainless prop is rusting, its not pure stainless or it would be too weak to handle the stress.

 

[joshb]

In the 10yrs since i built it he has fired a total of 14rds

I have done this! I built a 6br two years ago and haven’t fired it once! SQUIRREL!! I’m easily distracted.

 

[DickE]

Donovan.... I never thought that you would be the carrier to this virus. LOL.

 

[SEGARE]

Creeping Eruption.

 

[fatelvis]

I am in Pipeline repair and that looks amazingly similar to the damage caused by an amoeba like organism found in gas wells. It will attach itself to the steel of the pipeline usually in areas where condensate collects. There it forms a colony like structure and actually feeds on the steel. The result is a leaking pipeline or possible rupture. Same kind of wormlike lines.

Ahhh now I know what "Downhill" refers to. Welding!

 

[golong]

For those that are the metallurgist type, what are the chances these blanks have air pockets or chemical imperfections/contamination that show up once reamed? I kind of doubt that blanks are x-rayed, it is seems plausible that they would have imperfections that cannot be seen from the outside.

 

[kvd]

This appears to be filliform corrosion. I could see this occurring in a rifle barrel that hasn't been cleaned in a long time. This link may provide some insight.

https://www.corrosionclinic.com/types_of_corrosion/filiform_corrosion_underfilm_corrosion.htm

 

[1611]

I have found the same recently , that 50 dollar investment(Teslong) has changed my mind about collecting old deer rifles . Those shiny on the outside gems sure can be ugly on the inside.

I am still collecting them, for their actions. Those old 1960-70s Remington 700 rifles sure have some smooth actions and make good donor actions to build off of.

 

[1611]

Wait was this rifle ever in commie China? That might be coronavirus. Better quarantine it in my safe

 

[Rustytigwire]

Think of metal kind of like concrete made of stones and sand and gravel of varying size with cement holding t all together.
It has a granular or crystalline structure of chunks of stuff with smaller kinds of stuff holding it together.
Pour acid on the concrete, it dissolves the lime that holds the aggregate together but not the harder rocks that make up the aggregate itself.
Stainless and carbon steel are granular or crystalline with stuff between that holds the grains together. Corrosion attacks this intergranular material. Like dissolving the glue from chipboard. Big pieces still there, nothing holds it together.
Stainless saltwater piping leaks in weld heat affected zone after a couple years. Chlorides attack and turn perfectly good material into a metal crap sponge.
Corrosion happens unless you prevent it.
All you metal industry guys here are right!
Fascinating to get to see rotten stuff everyday and how it deteriorates!

 

[dolek]

For those that are the metallurgist type, what are the chances these blanks have air pockets or chemical imperfections/contamination that show up once reamed? I kind of doubt that blanks are x-rayed, it is seems plausible that they would have imperfections that cannot be seen from the outside.

Inclusions happen , anything is possible . While working at the forge you see some wild things when you heat steel.

 

[Nature Boy]

I have found the same recently , that 50 dollar investment(Teslong) has changed my mind about collecting old deer rifles . Those shiny on the outside gems sure can be ugly on the inside.

yep, I got one of those, but if it still holds minute of deer it’s good to go

 

[dolek]

yep, I got one of those, but if it still holds minute of deer it’s good to go

If I saw that one I would surely take a chance .

 

[dolek]

This one was shooting .75" at 100 when I pulled it,Remington 78 in 30-06.

 

[jsn]

From memory, most Moly for bullet coating is Molybdenum Disulphide, the sulphide portion comes into contact with water and starts to form sulphuric acid.

Varmint Al had photos of rust caused by moly use on his website years ago, but I don't remember them looking like the "slug trail" photos shown.

There are microbes that eat sulphur/sulphides underground.......

 

[DanS]

I have the same stuff in my SS Lilja 223AI