I always kind of snickered at the idea of "hard" primers. Then last fall I was building a project revolver and ran myself out of WW & Federal primers and had to use CCI 500s. They needed 8-10 oz more spring tension for reliable ignition in long shooting sessions (50+ rounds). A trial batch of 9mm with the same primers run through a stock semi had no issues.

Now, admittedly part of it might have been finger fatigue, but the issue didn't exist with the other brands of primers.

The question is, since the same outfit owns CCI, Federal and Speer, what primers are in what ammo? One sort of expects Federal in Federal but CCI & Speer?

Rastoff's got the right approach, see if your favorite carry ammo is reliable. But, shoot some long strings. After some exercise springs will let down slightly. FWIW, the long term practice with J frames has been to stick to stock hammer springs. They should reliably produce 50+ oz of hammer tension.