IMO that bit about CCI primers being "hard" is an internet myth. I will grant that the CCI Magnum primers are a touch harder than the Standard primers but it's almost a splitting a hair difference.

How can I be so certain of this, plain old experience. Now, this is a bit of a winding path so pay attention, those who post replies clearly showing ignorance of this winding path will get a yardstick busted across the back of their hand. Something that should still be used to motivate students paying attention. Yeah, it stings but only for a moment.

I clean my fired casing using stainless steel pins and the pins I use require flash holes that are 0.82 inch in diameter to insure that two pins won't jam in the flash hole. There is one single brand of commercial ammunition that I have found that universally have flash holes sized to 0.082 inch diameter. That brand is Remington UMC. So, any time I need to refresh my brass I pick up some bulk packs of Remington UMC and shoot them for nice fresh brass.

So I have shot a lot of Remington UMC in 38 special, 9mm, 40 S&W, and 45 ACP. I also have S&W revolvers in all of these calibers and I like to tune my revolvers to a consistent trigger weight. Back when I cleaned my brass in walnut shell media I could tune my revolvers to a consistent 8 lbs. DA trigger weight. Note, I have ALWAYS loaded with CCI Primers and did discover that a 7 lbs 14 ounce trigger pull on my 620 was occasionally unreliable with CCI 550 primers. Retuning to 8.000 lbs. solved that problem. After I found that REmington was thoughtfull enough to size their flash holes I found that 8.0 lbs was just too light, had lots of issues with misfires. Actually had to shoot Single Action with my 625 to use up the UMC I had with me. Experimentation led me to find that a 9.0 lbs DA trigger weight was what was necessary to light off Remington UMC. So I now have all of my revolvers tuned to a 9.0 lbs DA trigger weight.

PS: my 40 S&W caliber revolver is the 610, yeah it doesn't just shoot 10mm. I do shoot 357 Magnums and for those I use Starline brass and drill the flash holes out to a 0.082 inch diameter. Which is a royal PITA but if you load a case with a flash hole jammed by some stainless steel pins it isn't going to fire.