I bought 5,000 of these primers. I believe that they were Magnum Small Pistol Primers. The first 1,000 worked flawlessly, the second 1,000 1-3% needed a double strike to ignite. I blamed the need for a second strike on a 75B that had the springs and hammer changed out by CZC, but when a bone stock P-10C had the same issues, I blamed the primers. They are sitting in the garage until I get the ambition to see if something I have will ignite these first time every time.
This was two years ago, and your results might vary.