I think the recommendations of the experts are generally valid, but I am a mechanical engineer by trade and so I can use that knowledge and experience to determine whether a given recommendation makes sense or not based on its key assertions.
That being said, I do think people get a little carried away looking for the magic bullet, but it is human nature to get all the extra advantage, especially in a life or death situation, one can get.
I keep XM193 loaded in my AR's for self defense because
(1) the experts like it (for 16" + barreled weapons, with 1/9 twist like I have)
(2) their rationale for liking it, when fired out of longer barreled weapons at close range, is a valid set of reasons based on fluid mechanics and projectile design.
(3) it goes bang every time I pull the trigger
(4) a whole boatload of dead VC can attest to its lethality and massive tissue damage at close range when driven to a high enough velocity
XM193 is not the latest "wonder bullet", especially for SBR's, but it is still a proven and expert recommended round in longer barrels of slower twist (1/9, 1/12, etc.).
For the handguns, I have been a little more reluctant to let go of my 9's in favor of the now "expert" recommended gold-standard gold-plated .45ACP. I have 5 or 6 .45ACP's, but the 9 is still my favorite, loaded with Speer Gold Dots, of course
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