Here’s an interesting article on hydrostatic shock:
https://www.themeateater.com/wired-to-hunt/whitetail-hunting-gear/is-hydrostatic-shock-real
In 2007, a group of researchers writing in Neurosurgery called hydrostatic shock a “relatively recent myth” concocted by soldiers and hunters to explain observed injuries.
More recent research, however, points to a strong link between high-pressure bullets and remote neural damage…
…In experiments conducted in 2007 and 2011, the Courtneys observed hemorrhaging along the abdominal walls, rear rib cages, and brains of whitetail deer that had been struck by a bullet. These areas were distant from both the permanent crush cavity and the temporary stretch cavity, and the researchers concluded that “the most likely cause of the hemorrhaging was the pressure wave.”
Other researchers have reached similar conclusions. A famous series of experiments conducted by a team of Swedish scientists in the late 1980s discovered remote injury to peripheral nerves, spinal cords, and brains of pigs that had been shot in the thigh. Research published in 2009 reported “cufflike pattern hemorrhages around small brain vessels” of people who had been shot in the chest, which the researchers attributed to “a shock wave caused by a penetrating bullet.”
Even with the evidence for the efficacy of hydrostatic wounding mechanisms, the article concludes that shot placement is king in a hunting scenario. What has been observed and argued for a long time in defensive or tactical setting is that a significant portion of a rifle’s wounding ability has to do with indirect wounding and incapacitation, typically attributed to hydrostatic shock. This has been observed even with the most basic of bullet technologies, the FMJ.
Pistol wounding characteristics, on the other hand, have always been limited to the damage created by the path of the bullet due to a pistol bullet’s much lower velocity as compared to those coming from a rifle. Which explains why so much energy and marketing is poured into developing pistol caliber bullets that create the most tissue disruption possible, while still allowing for sufficient penetration to reach vitals.
It is my estimation that my slowing down rifle bullets to the point where hydrostatic wounding is mitigated, and then trying to make up for it with expanding or fragmenting bullets is an expensive, loud, and cumbersome way to turn a rifle into a pistol. By neutering what makes a rifle effective, namely velocity, one is relegated to using tech to try and make up some of that lost ground. But no amount of (current) tech will make up for something that only sufficient velocity brings to the table.
That said, having sufficient velocity AND superior bullet technology is clearly the best of both worlds. However, as the vast preponderance of evidence points, I would rather defend myself with FMJ rifle velocity rounds than the most technologically advanced pistol velocity rounds.