Max is lawyer proof on any modern firearm and many of my rifles group better the faster you push them. One thing I've learned is the rifle will tell you when it's getting too high. Quite a few years ago when I was stupider and drank I ran 3 grains over max in a 7 mag Steyr Prohunter. It Chrony'd a 140 grain at 3450 fps. and was laser accurate. The case never indicated any pressure problem other than a very slight flattening of the primer. No sticky bolt. No splits, No blown primers. It would ping when you shot it though due to the harmonics then it turned the crosshairs on a Pentax Lightseeker. Then I knew there was an issue.

Took that same round and put it in a Win. Model 70 and it blew the primer, stuck the bolt, and the case was ruined. I'd never do that now.

There is almost no end to the rabbit hole some of those guys go down. It gives me a headache when they really start getting into numbers and math. One video will say always do something and the next guy will say never do that

There are definitely a lot of rabbit holes and I've been down plenty of them. Some of the best advice does come from the competitive shooters though. The guys who are successful and have been doing it a while all will agree on one thing - if doing something in loading ammo doesn't make a difference on the target you're wasting time.

There are a lot of reasons the bullet companies arrive at a max load for their guides. The numbers have definitely changed through the years. I have several older guides with max loads for some cartridges that are WAY higher than the current guides. One reason may be the lawyers, another reason is that they didn't have the modern pressure testing equipment when they developed the loads 50 years ago. Excess pressure was determined when they got the traditional pressure signs like flat primers, sticky bolts etc. Truth is, those traditional indicators are NOT reliable and usually only show up when you have far exceeded SAMMI Maximum Average Pressure limits.

Another discussion would be when it MAY be safe to exceed SAMMI MAP limits. The 7x57 is a good example of this. Because of a large number of OLD rifles in this cartridge, loading guide data is absolutely lethargic. I will definitely push this cartridge beyond the max velocities shown in the guides when using modern rifles like my Ruger M77.

The 7mm Remington Magnum is another one that I will push to the limit and maybe a little beyond. When it was approved by SAMMI, it was given a lower MAP limit due to wide pressure variations in one bullet / powder combo. IIRC, this combo was with 175 gr bullets and H4831 powder. As a result, it was given a 61000 psi MAP instead of 63-65000 MAP like many other modern cartridges. Does this mean it isn't safe to push 140 gr Accubonds to 65000 psi? I'll let you guess what I think about that...

There are many other examples but it's important to understand that your gun and the chronograph will tell you when you've gone too far. If your load testing by raising the powder charge in 1 gr increments and your velocities suddenly show a large spread, you've probably pushed too hard. It's not really dangerous to find this point as long as it's a modern rifle in good condition. You really have to fugg up with the wrong powder to blow up a rifle with one hot load.

If you want to go down a rabbit hole about pressure go to the 24 HCF forum. Go to the archives thread and find discussions by the late Ken Howell. Brilliant man.

Good info, Thanks !

Yes, absolutely some great info here.

I've been loading for 20 years, and there's still a staggering amount of things to learn. Rewarding hobby is an understatement.

Actually great question!
When I start load development I find max pressure for that bullet /powder combo I'm after.

I work up in .3 increments to max most times.
Have to take into consideration if it's 50° or 95°

Every chamber and piece of brass are different and you have to find your max .your reloading manual is a starting point

Otherwise if your shooting mix match brass and different lots brass and bullets just load down or carefully approach max

I shoot all my brass on same number of firings

So no I don't shoot over max my rifle tells me at load development.maybe over book but I don't care my brass and extraction tells me so