I had a 220 swift REM. 700 that’d do that every time….could never see what would cause it.  For years i asked just about every gunsmith that I came across, why?

got a lot of guesses but nothing concrete.   My best guess is that in the rifling process sometimes the lands end up super sharp, and will peel the rod.

I actually ended up getting a brass rod, and bushing to clean that gun.