Pressure signs on brass and primers is very unreliable.
I disagree. The marks are very reliable, they are there, you can see them. What is unreliable is people's conclusions about what the amount of pressure producing those marks actually is...
The bottom line with brass and primer pressure signs is you can only be sure they apply to the particular brass and primers you are working with. They may or may not apply to the gun.
Agree with this, except for the last part. The pressure absolutely does apply to the gun. It HAPPENS IN THE GUN, for goodness sake. It applies.
Now, what doesn't apply is the belief that "excess" pressure is automatically a dangerous thing. All pressure signs are, are signs that you aren't where you ought to be. They don't reliably tell you how far beyond where you ought to be or WHY you are beyond where you ought to be, that part you need to figure out from other factors.
Whenever they show up, they are a sign you are not where you ought to be, with the specific combination of gun and ammo you are shooting.
For that, they are absolutely reliable. For anything else...not so much.
Cratered and flattened primers tell us something isn't what we want it to be. They don't tell us something is dangerous, or not, or WHICH thing it is.
I wouldn't call it a sticky bolt as much as it just takes a little more effort to open than the previous loads.
That's the definition of a sticky bolt. "Sticky ranges from "just a little more effort" up to having to hammer the bolt to get the action open. At that point "Sticky" turns to "frozen".
By all means, chronograph those "sticky" loads. See if you get any SIGNIFICANT difference in velocity. Significant is the key here. A double handful of FPS isn't significant. A few hundred, is . See what you get and decide for yourself if the gain is worth the additional stress on your equipment (brass and the gun itself)