And.........
QuakertownRich,
You mentioned top strap flame cutting. Several years ago, on another, now defunct forum, I was taken to task for using the term "flame cutting." The poster chided me, saying it was particle abrasion causing the cutting, citing me seveal experiments he had performed to refute the "flame" cutting action. My experience was this:
Years ago I was cleaning my Ruger Blackhawk .357 Magnum when I noticed a deep cut in the underside of the top strap just above the barrel stub. At that time I was using the Remington 125gr. SJHP bullet with, I believe, 9.0 grs. of (then) Hercules Unique powder. Shooting on an indoor range produced a very bright sideways flash, typical of Unique powder. The cut occured after about 2,500 rounds or so of this ammunition had been fired. (Yes, I do keep a count in a log book.) I continued to monitor the cut and it seemed to go just so deep then stop. So, I quit worrying about.
I recently examined my 6" Model 586 and there is the faintest of lines in this area, though this gun has been used mostly with Winchester 296 or Alliant #2400 powders. Also there is about an 11,000 round difference overall in the two guns, the old Ruger standing at about 17,000 rounds fired.
As to the advisor who chided me, his solution was to coat the area with graphite, even using a No.2 lead pencil to prevent the cutting action. His claim is that the cutting is done by powder and primer particles being blown out the barrel/cylinder gap.
I no longer give the problem any consideration.
Bob Wright