As far as the deformation of the bullet having any effect on rotation goes, I doubt it. GD
Just an idle thought I had while mowing the lawn. The story about the sound made by the Whitworth bullets always intrigued me; similar to the distinctive rip of the German 88s, which my father has talked about, on a much smaller scale of course.
That ratchet thing is an old idea too. I wonder if anyone is playing with oval bores these days. Those should be easy to clean, but might run up pressures with jacketed bullets unless maybe sabotted (patched) to cut friction.
