What for Wad or Filler ?

[smo]

LD, I think you may have answered your own question...

You said after you polished the 4” or so of the bore was when you first experienced the cutting in 6 tiny, symmetric holes.

What method was used to polish the barrels first 4”?

 

[Loyalist Dave]

What method was used to polish the barrels first 4”?

I used 600 grit emory paper with a few drops of oil, wrapped around a 1/2" wooden dowel, and then carefully moved it back and forth in the 6 grooves locations..., so I think I got the edges, but as Appalachian Hunter pointed out, it may also be the edges of the crown. So I might have had two problems. The sides of the lands AND the crown. I chose the 4" portion because when loading that's where the most resistance is. Of course I understood the risk that the cutting may be caused by burrs deeper, and that what I was feeling when loading was the first part of the problem.

LD