I can't thank you all enough.
I didn't expect to learn about pistols and revolvers on ARFcom, but I am so glad I wandered over.
The S&W 929 has been an absolute gem to shoot. Aside from how interesting the moon clip operations have been, the pistol is fantastic to shoot and right out of the box!
I ran the first night with the iron sights out of the box and the rig was dead on at 25 yards using Winchester 124 gr NATO loads. A real pleasure to shoot a rig that hits where you point it!
I even surprised myself by being able to get a decent focus on the front post by using a Merit aperture on my safety glasses. I had to go to the smallest setting, but it made the post crisp. I was able to call the shots.
The second night I showed up with a Burris Fastfire mounted on the rig, and again it was a blast! I also tried some Rem 115 loads and there was about 2.5" left shift in the group at 25 yards, but another tight group in any case.
The double action shooting has never been my game, but with this rig I will go give it a try. I may even add one more moon clip rig in .45 just for fun!
Thanks to all for the background research and advice!