Bore Scope Question. Pictures

[whyhatchu]

Anybody know what this is inside the barrel? Brand new nitride barrel.

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[Barang]

copper? grease? did you already push a patch through it to see if it get transferred on it?

[ar15barrels]

Looks like copper from test firing.

[divingin]

A copper solvent will tell you pretty quick. Wet patch, wait a minute or two, and wet patch again. If it comes out blue (using something other than KG-12) it's copper.

Color makes it look more like grease, but that can be misleading with all the color handling of electronic devices.

[tabascoz28]

Some guns get test fired and some guns don't. That should be copper.

[dougd1015]

Copper.