If you read through
this fairly thorough discussion based mainly on congressional hearings about failures in the XM16E1 in combat, you learn several key things. One is that the original firing pins were heavier and therefore more prone to slamfire than current firing pins. Another is they had some improperly specified primers in the 1960s and that with properly specified ones, even the heavy firing pins were much less prone to slamfire. Finally, they had a positively criminal problem with mis-specified powder that resulted, among other things, in a 200 Round per minute full auto rate of fire increase that slammed the BCG's both rearward and forward harder than current AR's and military BCGs run, and that increased the momentum in the firing pin. With those things fixed, current versions are not so prone to slamfires.
The thing to keep in mind, though, is that less sensitive primers are part of the combination of changes that solved reliability problems.
The final military primer sensitivity specification is matched by the sensitivity of both the CCI #41 and the Federal GM205MAR primers. The order of increasing sensitivity of the CCI primers is CCI #41, #450, and #400. The #450 is more sensitive than the #41 because of the different anvil (information from a past phone call I had with them, as well). The wider spread angle of the anvil's tripod legs makes it shorter and less rigid in opposing the firing pin blow. It also makes the finished primer on the shorter side overall, so it has to be seated a little further below flush with the case head to achieve optimal reconsolidation (bridge set), which also reduces the indentation made by the firing pin's inertia when the bolt closes (high primers contribute to slamfires). The #400 is more sensitive than the #450 because,
according to James Calhoun, its cup floor is 20% thinner than the #450 cup floor (but that is 1995 information, so it would have to be confirmed by the manufacturer to be sure it is still so).
I don't have a confirmed sensitivity order for Federal primers, but I do have an email from Federal stating the GM205MAR, as compared to the GM205M match small rifle standard primer, uses a thicker cup as its means of reducing sensitivity to the military spec level.
I don't know the practical concern with slamfires in the AR after the firing pin and powder issues are addressed. I don't recall hearing them happen when the command to load is given on the firing line at matches the way the Garands used to have periodically. I know the late Glen Zediker, back when you could get them, said he would buy new primed Winchester brass and use it for first loads without modification, and Winchester SR primers have none of the special sensitivity reducing steps taken on them. But Zediker would have used a gun properly in spec, and with all the DIY builds and brand variations around these days, I am less sanguine that all guns would be equally slamfire resistant when using them.
