Copper residue in necks

[PJ1]

First time I have seen the bluish green copper flakes inside of the necks. Same powder, bullet lot, brass. Something that I need to be concerned with? Maybe chamfer/trimming residue?

 

[rwj]

Another potential source is bullet jacket material being shaved off during seating. It’s easy to leave a small sharp edge/burr during neck ID chamfering, especially if the tool is becoming dull. You can test by seating/removing a bullet then inspecting its bearing surface for scratches.

 

[dmoran]

 

[jepp2]

View attachment 1306938

What did you use to polish them? Those are beautiful! Bullet jacket scraping is BAD for accuracy.

 

[dmoran]

@jepp2
Steel wool (fine) wrapped around used bore brushes, spun with a drill .... is my way.

 

[RegionRat]

First time I have seen the bluish green copper flakes inside of the necks. Same powder, bullet lot, brass. Something that I need to be concerned with? Maybe chamfer/trimming residue?

At what point in the process did you find this?

For example, I shot them last month and looked at them today… or?

Blueish green in this context is called verdigris and is likely a copper oxide.

There is copper in the brass, as well as bullet jacket alloys. Depending on what step in the process you are looking at, this means you have some oxidation.

Lots of things can cause this. Water, acids, heat, etc..

 

[PJ1]

At what point in the process did you find this?

For example, I shot them last month and looked at them today… or?

Blueish green in this context is called verdigris and is likely a copper oxide.

There is copper in the brass, as well as bullet jacket alloys. Depending on what step in the process you are looking at, this means you have some oxidation.

Lots of things can cause this. Water, acids, heat, etc..

This was maybe a day or two after shooting. Thinking about what you have said gets me to thinking that high humidity ( light rain that day ) maybe the culprit. I never shot with light rain in the air until that day. Whenever I have shot in the past, weather has been of lower humidity.

 

[RegionRat]

If your cases were allowed to lay for a while and there was light rain that could get to them, it is possible that is all there was to it because most times rain picks up things in the atmosphere and has a pH that is low enough to cause this.