By far the most reliable sign is web expansion, followed by ejector marks, enlarged primer pockets and cratered primer indentations. The problem being that most of these overpressure signs only manifest when the pressure exceeds 75kPsi.

Please can you expand on this ...

Measure the web with a micrometer, shoot the shot and then measure again to see how much it expanded.

How the web expansion method works
Prepare and measure unfired cases:
Use new or once-fired brass from the same manufacturer/lot (brass hardness varies significantly between brands and even lots).

Use a high-precision micrometer (ideally one that reads to 0.0001" or 0.01 mm; a standard 0.001" micrometer is often not sensitive enough). Blade or ball micrometers work well for the narrow area.

Index the case (e.g., with a marker line) for consistency.
Measure the diameter at the web (just above the extractor groove) multiple times, rotating the case 180° for averages. Record the baseline (unfired) diameter. Some reloaders lightly file the rim slightly so micrometer jaws fit better without the extractor groove interfering.

Fire the load and re-measure:
Fire the cartridge in your specific rifle.
Clean the case and re-measure exactly at the same spot on the same case.
Calculate the difference (fired diameter minus unfired diameter). This is the web expansion.

Interpret the results:
Typical guidelines (these are rules of thumb, not universal absolutes):
0.0005" (0.5 thousandths of an inch) or less expansion on the first firing is often considered safe or near maximum for many loads/brass types. Some sources treat even this as a sign to back off.
0.001" or more is widely viewed as excessive, indicating high pressure. Once this level is reached, the cases are often retired from further "pressure testing" use because resizing dies don't fully restore the web diameter.
Larger expansions (e.g., 0.0015"+) or rapid increases signal that primer pockets may loosen soon, extraction may become difficult, or you're approaching (or exceeding) safe limits for that brass/rifle combination.

Measure the web with a micrometer, shoot the shot and then measure again to see how much it expanded.
How the web expansion method works

Thank you really good info
Going to use this step by step starting now
Might need a new blade micrometer ?

Just had a quick look

To make this meaningful ....

You are going to need a high definition caliper / digital / dial for 0.000 mm
You are also going to need a blade micrometer also 0.000mm
You are going to have to measure VERY carefully
The distances you are measuring are tiny

There is a cheaper way. Do not scratch the lion's balls by staying away from high end loads. Speed data is available from the propellant companies, so be conservative and avoid high pressure.

The normal reloader do not need this. Stay within the normal min-max range as per reloading manuals then you are safe.

When you want to colour outside the lines you need to pay the price; either expensive tools or run the risk of blown up guns. Most of the the more reliable signs only show when the pressures go over 70 kPsi hence the requirement for specialist tools.

When you want to colour outside the lines you need to pay the price; either expensive tools or run the risk of blown up guns.

Over and above the tools you also need skills, experience and competence in their use. Unless you have done a fair bit of high precision work, know what you don't know and what the consequences of that could be you are deep in FAFO territory.

There is a cheaper way. Do not scratch the lion's balls by staying away from high end loads. Speed data is available from the propellant companies, so be conservative and avoid high pressure.

Agreed
Use the reloading manuals start low and work up - the Golden rule
However in order to achieve 100% powder burn and above 90% case fill takes some "adjusting"
Particularly as powder choice here is very limited
Most .. magnums perform best near max loads

I would like to get the necessary tools anyway - I have a "fetish" for tools
Waiting for someone to design and market an easy accurate affordable way to measure pressure

There is this ...

https://www.youtube.com/watch?v=kWXRuzbS7ZY

But I do not have .. millions  :'(

Here are some interesting remarks about absolute pressure measuring.

https://forum.accurateshooter.com/threads/how-to-measure-chamber-pressure.4097368/

Here are some interesting remarks about absolute pressure measuring.

https://forum.accurateshooter.com/threads/how-to-measure-chamber-pressure.4097368/

"Get in contact with Bill Wiseman" ...

Bill Wiseman & Co, Inc

People - Industry / Military DO test for pressure

There must be something in it ?

Even just to satisfy curiosity ...  😉  🙂