There’s a pretty thick layer of cake in there. I would knock it down with a pipe knife before sanding it. Of course you’ll need a pipe knife and have figure out how to use it.
The are reamers that’ll do the job too. It’s my experience that reamers do more damage to a chamber than any other tool available. People tend to overuse them and apply way to much pressure, which removes the floor of the chamber, leaving the draft hole over on the side of chamber and parallel to the chamber wall. As the burn progresses the ember tends to move over to the back of the chamber leaving unburned tobacco in the front of the chamber. In the afore mentioned scenario, people tend to stir the tobacco, tamp and relight. This repeats until you burn down enough soggy tobacco, and burn the hell out of the draft hole…
Sanding is the least intrusive as long as you don’t try to push the paper through the other side of the pipe. A few light spins should be enough to remove a sufficient amount of cake to keep it from becoming too thick. I use 220 grit to even out the cake in my chambers.
Out of round chambers, wavy chamber walls, and the messed up positioning of the draft hole are the results of poor technique in maintaining a chamber.
I’d check with the B&M and see if they can remove and smooth out the cake for you. If so they can probably give you some pointers, or provide the necessary tools. It takes a little practice to do it right, but the learning curve is not steep. Over time you’ll get to now how often to do it, and won’t ruin a chamber by over zealously sanding, reaming etc.
. What B&M is selling uncleaned, un-reamed "estate" pipes? having said that, its a beautiful straight grain pipe, ream it and move on, its fine.
