The reloader cannot accurately predict chamber pressure based on external observations like bolt lift or primer appearance, or the absence of those indicators.
I tend to follow the observation that when velocity stops increasing in a linear fashion with the trend line or reverses, that I may be over max pressure at that point, or more simply, that the benefits of continuing to add more powder and pressure and the resultant velocity benefit is at a dead end.
But outside of having a calibrated strain gauge all this is largely guess work and speculation, so why even go there?
As a reloader for many decades, I refer to the valuable resource of data collected at great expense as provided by the manufacturers, developed by highly paid expert technicians in their very expensive laboratories after countless man-hours of dedicated research...all for free. I like free.
I am usually comfortable working up to max published loads more often, but sometimes not, and there is usually no benefit to exceeding max published loads for that last 50fps, I am mostly interested in finding the most accurate load with moderate pressure, and without burning up pounds of powder in the process.
I check the published lab results against my chrono readings to find out where the rifle and components I am working with are at on the spectrum. Chronos are subject to measurement errors, but are close enough on average.
I'm not a fan of RL-22 but it is a very popular powder for all it's quirkiness. I do prefer the single based powders in that burning range.
Internal ballistics is a manufacturing science of average results in a world of many random variables, so there's no need to confuse yourself by overthinking it.
