Thread: Bore Rust?

Problem with rust pitting in the bore is it will cause fouling (particularly copper) after a few shots which is detrimental to accuracy.....OK if the shots are few, but a competition barrel shooting strings is toast if it is pitted....! And as @XR500 noted it will continue to rust despite having oil on it.

One could try and convert the rust (iron oxide) to iron phosphate by treating with phosphoric acid, but that will only stop further rusting, not fouling.....!