Need Experts Help

[jmoore]

jmoore - explain "cord worn" please

The cord used for cleaning could abrade the chamber, throat, and/or commonly, the muzzle whilst being pulled through the barrel.

Oddly, my rifle seems to have no other damage in the bore, but I can't think of much else that would create this sort of "washed out" area in the chamber. If your rifle shoots fine, it's nothing to worry about.