I noticed the rifling on my new model 57 smith 41 mag looked a lot sharper to me than some of my older ecm rifled smith. I was curious and called Smith and a tech told me they were using another process that was more like the old broaching method. I know some had had more leading with ecm rifling so maybe this is better? My new 41 mag does not seem to lead bad. I had some with Lyman 410459 220 at about 1150fps but my bullets were too soft at 8 bhn. Anyway, I thought that was interesting and the rifling does look better to me. He said they started with the process about a year ago.