A reamer is rotated to do it's cuting. It will in fact produce radial marks, not axial ones (Aerospace Machinist). This does look like a rather rough reaming job, but may just be the magnification of the pics. I don't believe that was the problem in any case. Axial marks would be produced by a broach, but that is not how a chamber is cut.

Miller/TN
I Didn't Say Everything I Said, Yogi Berra