That article misses the mark in several ways. Most obvious is that the author incorrectly cites SAAMI maximum pressure for .38 Special at 21,500psi. A cartridge loaded to that pressure would actually be a +P+ loading as SAAMI max for standard pressure .38 Special is 17,000psi and .38 Special +P is 20,000psi.
Secondly, the author assumes that, because a loading with a given bullet weight delivers higher velocity than another with the same bullet weight, that the pressure must automatically be higher. Pressure and velocity do not necessarily correlate directly with each other and it is entirely possible for one loading to produce both higher velocity and lower pressure than another. For proof of this, one need look no further than a reloading manual. If you look at the maximum loads with various powders for a given cartridge, bullet, and primer, you will find that some develop much higher velocities than others even though none of them exceed a certain pressure limit. What correlates much better with velocity is how long the peak pressure can be maintained. the way in which boutique ammo houses like Buffalo Bore, Double Tap, Grizzly, and Garrett are able to deliver higher velocity without exceeding the maximum pressure is that they carefully select and blend powders with particular burn rates in order to sustain the peak pressure for as long as possible.
Finally, the author of that article relies only on advertised velocities for loadings of yesteryear to prove that they were higher pressure. As most of us know, it is not particularly uncommon for factory ammunition to fail to live up to its advertised velocity and this phenomenon is hardly a recent development. Actually, ammunition makers have been forced to become much more honest about their velocity figures over the years because chronographs are both better and more widely available than they were in years past. Today, anyone with a couple hundred extra dollars can easily buy a chronograph and see just how honest the manufacturers' velocity figures really are. The author cites advertised velocities from as far back as the 1920's, but unless he's actually chronographed vintage ammunition (he makes no claim that he has), then he really has no idea how fast they are beyond the manufacturers' word. Likewise, pressure testing equipment is much better today than it was in years past. One of the reasons that many of the loads listed in various reloading manuals have been reduced over the years is that newer, better pressure testing equipment exposed many of those old loadings as being much higher pressure than what they were originally thought to be. While S&W K-Frames and Colt D-Frames may have once thought to have been up to .38/44 and other high-pressure ammunition, those recommendations are long gone and have been replaced with much more sensible ones by the manufacturers of said guns.
The only possible way that it could be proven that today's +P ammunition is nothing more than the standard pressure of yesteryear would be to both chronograph and pressure test both current and vintage ammunition on modern equipment. Until someone does that and provides their findings, however, I'm going to classify the current +P=old standard pressure as and unwise, and potentially unsafe, speculation.
