Well it turns out what it is, is that the screw hole underneath the top strap is directing powder fouling directly on the side of the cylinder and causing “half moon” shaped deposits of fouling which felt like dimples. I was mistaken and obviously I need more experience with revolvers.
Bobster, thank you for your interest in my question and sorry if I wasted your time. However this is why this is the only forum I belong to; people are actually helpful as well as wanting to help.
And thanks for the article!!! I much love this model 19.
And also it’s a new model I got from an older friend of mine (he is a retired police officer and he carried a model 19 back in the 80’s) and I mostly shoot 38’s and have only put one box of 357 ammo thru it so far.
