The ugly bore below is not one of my bores, but those straight tracks are present in one of my 1894 rifles.  My bore has good rifling.  .32-40 DOM 1904.

I have cleaned the barrel well, but these lines seem unaffected.  I thought perhaps they were somehow cut by an undersized bullet (but that would have to be a wonder-bullet to travel in such a straight line down the bore, and the lines are unbroken.)  I figured maybe it was from a cleaning tool being shoved down to aid in removing lead.

I hadn’t seen other bores with these tracks until I came across this photo today.  Without checking for certain, the photo’s tracks are the same width/depth as are my rifle’s tracks.  Photo is of a ’73 .38 WCF.

What causes these tracks?  Are they detrimental to the accuracy of the rifle?  (I have yet to shoot this rifle.  I know taking it out for a spin would answer this accuracy question.)

If they are just scratches in a leaded barrel, what is the best method/material for removing the lead?  I have brushed the bore with threads from a “copper” sponge–didn’t seem to make much of a difference.

My attempts to photograph the tracks in my bore didn’t work out so well.  They do not appear to be the equidistant sets as in the first photo, but they are.