Remember when WW2 surplus Mausers etc… could be found in barrels at Army-Navy stores?
Yeah I’m that old 
A disproportional number of these service rifles could be observed having deformed muzzles because many service rifles employed “pull through” cleaning kits stored in the buttstock. After heavy use in the field the cord would get imbedded with dirt and erode the crown of the muzzle destroying accuracy.
With Bore snakes as with any pull through kit, it is important to always pull the cord straight up and out, without contacting the crown.
2 Likes