OMG! I'm getting a head ache reading this. I can see the merit in MD's writings. I admit I have been of the opinion that a flat primer meant it was time to back off. But reading this thread is enlightening me. I may be getting ahead of myself here but i'll make this statement. I believe that if you have a real case of high pressure that you will ;probably see a flat primer. But you will see other tell tale signs as well because after reading MDs post I believe that there are at least a couple different things other than pressure that can cause a flattened primer and that if you have a flatten primer and no other signs of high pressure you probably haven't experienced high pressure. The few times I've experienced real high pressure there were several signs of it. One, and the first thing I noticed was a sticky case and hard opening bolt. Another big one that will go along with that is wildly fluctuating velocity and accuracy or just abnormally high velocity. And the biggy, the one that's not readily noticed is an excessively expanded cartridge case base which is determined with the use of a micrometer. Of all the signs I've ever heard of that one is my main one that makes me believe I've experienced excessive, potentially harmful pressure. But I also think that you'll see more than one sign if it's really high pressure. Like I said. correct me if I'm wrong because these are just my opinions.
Last edited by Filaman; 06/15/21.
