I've seen marks like that on .45 ACP brass before. It was caused by the breech face not being machined flat all the way to the edge. In each of the three guns I've fixed there was a small, almost imperceptible step up at the very edge of the breech face on the ejector side. Careful filing...
If you're determined to take the sideplate off I highly recommend Jerry Kuhnhausen's shop manual on S&W revolvers. And the value of quality screwdrivers that fit cannot be underestimated!
While it's very true that there's no "need" to take the sideplate off for cleaning, some of us are...
I have only loaded the 125 gr. XTP's so far (a box of 158's is sitting on my bench but that's as far as it's gotten so far).
I use CCI 550 primers and 14.9 gr. of 2400. I get 1800 and a little out of a Marlin and 1150 out of a 4" L-frame. I could load hotter and get more velocity out of the...
I got a ProChrono about 5 months ago. So far it has worked pretty well. The only time I've had any trouble was when I tried to use it when it was sprinkling just a bit. I'd prefer a setup where the sensors and the computer were separate but I decided that was less important than getting...
I have a model 31 that is a square butt. My first try was a Pachmayr Compac style grip (item SJ-CS according to the packaging). I liked it a lot but my wife didn't and it's technically her gun. :-) So I put the original grips back on and added a Tyler T-grip. Now it feels pretty much like...