Col. Cornelius Gilliam, SASS#5875TG

Local gun club has a pin match that does have a single action category. 5-pins, must completely clear the table. Uses two single actions. Reload if req'd. A lot of fun, I've done quite well with 45 Colt, 250gr SWC, 800 fps loads. As mentioned above, loads approximating 45 acp hardball ballistics work best - have to clear the pins off a wide table, not just knock them down. Light loads are not allowed, too much bounce back. Finish up the match to completely destroy the pins with a shotgun category, 00 Buckshot or slugs only.

In the high power rifle world (223, 308, 300 win mag, etc.), the high pressure causes the primer pockets to expand and get loose over time and will loose a primer, locking up the gun. I've never seen it with a low pressure 38 special, but it's possible the cases has been reused so many times the primer pocket could enlarge.

I have bottles of both the Australian and Canadian. I can confirm that in my case, they are different colors and different densities. My older Australian powder looks like your pictures. Loaded to the same charge weight, the newer powder produces a consistently slower velocity.

Yup! Of course, I won't have a gun that doesn't reliably fire all of the main brand primers.