It's generally regarded that CCI produces the hardest primers, and this has been my experience as well. But what ammo manufacturer generally produces the ammo with the hardest primers? I know a milspec round like Lake City 5.56 or something will be the hardest primed, but I'm curious who you think makes their ammo the hardest primed across the board, from .25 ACP to .30-30 to .38 to .45-70, etc. PMC? Winchester? Remington? Black Hills? Hornady? Who do you think?

Well, if you feel CCI has the hardest primers then in turn CCI and Speer ammo will have the hardest primers too since both are made with CCI primers.

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I've used most brands and other than two duds in a single pack of CCIs many years ago, I have noticed any difference between brands. They all do what I require of them--go bang.

So is there any way of knowing which manufacturers use which primers? Of course Winchester uses their own, as well as Remington, but what about PMC or Hornady or Black Hills? This is all out of curiosity

All large rifle primers (standard and magnum) are ~0.025" thick.

All small rifle primers (NON-MAGNUM) are ~0.020" thick.
These thin primers are unsuitable for full-power 5.56 NATO loads (piercing and extrusion).

All small rifle primers (MAGNUM) are ~0.025" thick.
Use these for 5.56 NATO loads.

CCI offers the #41 "military" primer. I am unaware of the thickness of the #41 primer. Some AR15 shooters have reported misfires with the #41. This could be caused by various factors. After experiencing a large number of failures with the CCI "standard" small-rifle primers (size #400) in my AR15's, I switched to the CCI magnum small-rifle primers (#450), and I experienced no further failures. I have enough 450's to last me until Obama is collecting Social Security. So, I probably wont' be testing any #41's.

Much "commercial" cartridge brass will be relatively "soft" compared to "military" brass. This may give the shooter the impression that the primer is "soft" as the primer pocket may fail sooner with commercial brass.

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