Rocky, I will GUARANTEE that my loads were well above "Plus-P" levels. They pre-dated that concept by a LONG time, meaning that there was no such category as Plus-P. When my 358156 bullets were departing at 1200+ fps, they were a long jump ahead of what became known as "Plus-P". So were Lee Jurras' Super-Vel .38 loads.
We were well-aware that 2400 only got to burning well when pressures were elevated...that's WHY we used 2400 instead of the faster types. We were looking for performance, and we got it.
"Lucky"? I don't think so. My loads were much the same as a whole bunch of fellow shooters in my area, and no one reported any untoward occurrences. This was a sample of at least twenty other very-active handloaders and handgunners. If there had been a problem, it would have shown up.
There has been an enormous amount of second-guessing in on-line websites about the loads and practices of those who started in this hobby decades ago. I will only repeat my mantra regarding those days, those loads, those practices....THEY WORKED. So, things moved on, and most of us moved on along with them. The salient fact though is simply that we AND our guns were not harmed by the loads in common use at the time.