Here are a couple more observations about the XDs–first, in regards to feeding and, second, in regards to the Trijicon HD Night Sights.
The 200 SWC over 6 grains of Unique continues to prove itself as a reliable, and even easy to shoot, load. (The same load achieves 955 fps out of a 5" 1911. I won't be able to take a measurement with my chronograph using the 3.3" barrel of the XDs until the weather improves.) In regards to feeding, I think it's important to be aware of the following. After both measuring the length of the chamber of the XDs and checking for fit of the 200 SWC cartridge at an overall length of 1.23" by dropping it in the disassembled barrel (for which there was ample room), I loaded two dummy rounds in a magazine then cycled the slide first by using the slide release then by slingshotting the slide. Using the slide release to chamber the cartridge has always worked flawlessly both in tests and on the range. However, the XDs is finicky about being slingshotted.
It's already been observed that, "The problem, as always, with shortie 45's is breechface overtravel past the magazine well, which is limited...The tendency is for the slide to outrun the magazine." Moreover, the feed ramp is fairly steep. At 1.23" the cartridge has a tendency to get pinned against the feed ramp when attempting to slingshot it into battery.
Hoping to retain the option of the slingshot, I shortened the OAL of the 200 SWC cartridge to 1.22". I then loaded two dummy cartridges into the magazine and retested. The shorter cartridge chambered reliably. I then filled the magazine and retested. It worked fine.
I eventaully decided to shorten the XTP cartrdige from 1.23" to an OAL of 1.215" for the same reason.
I'd be interested in reading your observations about this, John. And the observations of anyone else. As I'm not sure I fully grasp all the variables at play here. It would be nice to understand the mechanics of the issue to ensure the reliability of getting the XDs into battery.
As to the Trijicon HD Night Sights: as is mentioned in my previous post, they shoot low using a 6 o'clock hold. When, at 7 yards, I covered the 2" bullseye with the orange dot, the best groups were located on the bottom arc of the bull. What's odd about the whole experience is that I got an email from Trijicon advising me to use the 6 o'clock hold: "All of the Trijicon Night Sights are designed for the 6 O’Clock hold." There you have it.