ORIGINAL: bigcountry
You ought to do what I did. I went on a quest when starting reloading to see what the indicators look like. so I loaded up some shells past max in .2gr increments. What I found, is flat primers are a great indicator. Cause if your not sure your overpressure over flattened primers, you probably are not over pressure yet. I saw withing 1.5gr over max primers that looked like it was part of the brass head it was so flat, and bolt lift started to get tough.Now thats a flattened primer. I found on one case not only flat, but pierced primer. I decided not to go further and find out how much it takes to lock the brass up in the gun.
I would find out about that 2 or so years later when taking a partition load, and trying to put it to a trophy bonded bullet. Not only flat primer, but had to take a cleaning rod and knock out the brass gently.
Federal is always going to look flat, and winchester and CCI will give you good indicators. But when your well over max, you won't have to scratch your head, you will know a definate yes.
I have no doubt that your observations and impressions were accurate. However, whether or not a primer appears flat, or has other "signs of excessive pressures", such as a pierced primer, can vary significantly due to factors other than excessive pressures. Primer fit in the primer pocket, thickness of primer cups, softness or lack thereof of the primer cup material,the strength of the striker/hammer spring, and shape of the firing pin are some of these other factors. This is why I do not consider the appearance of a fired primer to NECESSARILY be a reliable indicator of excessive pressures! Yet, with the other indicators of excessive pressures you listed along with flattened primers, you are no doubt correct IN THE INSTANCES YOU DESCRIBED.