"Next question is, at what PSI do these signs appear? We are all taught to look for them. Once we find them, back down a 1/2 or a full grain so they basically go away. Are the loads now safe and withing safe pressures for that cartridge? How would we know if we do not know at what PSI they develop in the first place?"
Goodness, the constant seeking of precise wild azz guesses; all that would be amusing if not so dangerous. Common sense has to play a part in everything we do snd no 'web rule' is going to substitute for that. Backing off a half grain in a too hot Hornet charge might be all right but it would mean little in a 7mm STW. Making the signs "basically go away" is better than not but it sure doesn't bring pressures down to established safe limits.
It's the fact that we don't know, and cannot know, much which makes following book loads from people who do know critical, and understanding even that can be exesssive for individual rifles is our only guide.
