"Dark bore"- what does it mean, what are causes, what are solutions?

[nntw]

I've read the expression "dark bore" a few time-it comes up during a 'search', but as a description, and it doesn't seem to be defined anywhere.

I'd assume it means exactly that- a bore that doesn't look bright and shiny.

But is this a result of corrosion during storage, or bad ammo ...? Would a brand new barrel always look shiny inside?

I'd assume that even if it's 'dark' due to surface corrosion, with no pitting visible, the use of a copper brush and cleaning solvents should be enough to clean it up.

But not having had to deal with this situation, would like to make sure I understand it, and also, what kind of effort (how long cleaning, etc) could be required.

Thanks in advance for clarifying this.

 

[Glock4ever]

"Dark Bore" to me means that the bore is rusted/corroded... it is never a term that I have heard for bores that are just dirty. As well you can see the difference between a dirty bore and one that is "dark". Frequently, I see dark bores on old Milsurp rifles and many times you can't clean the rust out well enough to make it nice and shiny. If you have a bore like this - I have seen guys clean and clean and clean but the bore never gets rid of the rust. Patches will keep coming out dirty...

 

[sunray]

"...assume it means exactly that..." Pretty much.
"...corrosion during storage or bad ammo..." Could be either or both.
Like Glock4ever says, cleaning 'em is next to impossible. Dark bores don't always mean the rifle won't shoot anyway.

 

[nntw]

Thanks for the responses. Appreciate the feedback.

 

[donor]

M95 Steyr I have was sold to me as having a "dark bore".

After a day of cleaning it turned out that "dark bore" was simply bore filled with old hardened cosmo mixed with powder and copper residue.

None of its previous owner cleaned it properly.

My point-"dark bore" might mean " I didn't know how/didn't feel like cleaning it"

 

[b72471]

AHH the dark bore

This term can mean anything from something salvageable to something that is totally screwed and will never shoot. I would avoid a rifle using this description unless the seller is prepared to give you a 3 day non shooting inspection.
Take care and be careful of half @ssed descriptions.

 

[Arctic]

If the bore is just dark cosmetically, a few rounds of fine, firelapped, will usually clean it up. Sometime they turn out to be good shooters!!