I wish this were posted somewhere you did not need an account to read it:

Matt Tardio on X: “Charlie Kirk “Mystery Bullet” Explained” / X

The summary is:

This analysis draws on two major U.S. military sources: the 1962 U.S. Army Medical Department report Wound Ballistics, which compiled data from multiple surveys covering thousands of casualties from World War II and Korea, and the 2012 technical report by two U.S. Air Force Academy researchers that provides a detailed study of the ballistics of the 30-06 cartridge.

Analysis

A deformed, wobbling (yawing), non-bonded bullet, traveling at an estimated 2,507 feet per second, that is designed to mushroom and deform upon contact, likely began to tumble by over 90 degrees within 3″ of tissue, separate and fragment, dumping all of it’s 2018 ft-lbs of energy within just 6 inches.

I am skeptical this can be used as a definitive answer to the questions raised because it seems unlikely the U.S. Army had access to statistically significant human wound ballistic data with 30.06 cartridges using soft-point bullets. Military ammo is full metal jacket with more recent allowance of the use of match grade hollow points where the hollow point is an artifact of the construction rather than a deliberate design to increase the ability of the bullet to wound.

That said, through and through shots for elk with this bullet type and weight (the claims I have seen are 150 grain Remington Core Lok), are far from certain. With deer they are mostly certain. But these shots are mostly through the lungs which are much easier to penetrate than muscle. So, with a young, large man like Kirk, a bullet losing its jacket and fragmenting in a neck shot, as the autopsy claims, then the main bullet fragment hitting the spine (I don’t know about this part) it seems plausible that it might not have exited.