The main reason for this discussion are firearms with free floated firing pins
such as the M16 (AR15), M1 and M14(M1A). Any semi's with a firing pin
spring is likely not going to have an issue.
I have used Remington 6-1/2 SR primers in my 5.56 loads and have not had a
slam fire yet. I do not like using them however with the supply issues we
have had in recent years, I did not have a lot of choice. But whether I have
used a "soft" Rem. 6-1/2 or a CCI 41 (Mil spec) primer I still always get a
small dimple on the primer of any cartridge I load in my AR's.
Seating below flush is a requirement to minimize the possibility of a slam fire.
I attached a excerpt from, Sierra's Reloading Manual, Edition V, on priming
cases for "Gas Guns". The manual has an excellent write up on reloading for
gas guns, and is well worth the read.
An Armed man is a Citizen,
An Unarmed man is a Subject. -- Unknown
"I am prepared are you?" -- Shade
"Regulation, registration, confiscation, domination, that's the Progressive agenda." -- RED Caddy