I agree that there might be a cleaning issue involved here. But if you've got pits that close to the muzzle . . . Think of it this way: Ever see a ported barrel? If holes in the barrel out at the muzzle don't hurt anything, why should you worry about pits in the same vicinity? They're only cosmetic in that area. Any pitting will decrease the value of a gun somewhat, but how dangerous it is or how much it will decrease the value depends both on the location and the extent (and/or depth) of the pitting.
