Handgun - Knockdown Power vs Concealment

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held 12 in the clip,

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Hmmmmm

Shot placement is more important than “knockdown power”. A full size 9mm that holds almost 20 rounds will work just fine.

Placement matters more. Instructor I know uses less powerful loads instead of the plus P rounds so he can have better placement.

Conceal carry. Small frame/grip so smaller caliber makes the most sense. I have a 9mm that can handle +P loads. Best compromise of everything.

I have a full size M&P with 15 round capacity in 40 caliber I have for in my truck and home defense. Too big to conceal, but big enough that it feels good when shooting it with the bigger rounds.

I’m pretty happy with the two, knowing the limitations of each.

“Knockdown power” is a myth created by Hollywood movies literally knocking down people with a shotgun blast. None of that would happen in real life. And while I get that using the term “knockdown power” casually doesn’t necessarily imply this blatant ignoring of the laws of physics, it perpetuates bad information.

The terms you’re looking for are “muzzle energy” and “terminal performance.” Both more accurately describe how defensive rounds can incapacitate and “knock down” an attacker by causing blood loss, bone breakage, or damage to the central nervous system.

As for your question pertaining to .40 and .45, I’ll tell you what I tell all my students in my concealed carry classes - 9mm Luger, .40 S&W, and .45 ACP all pretty much do the same thing given you’re using tested and proven hollowpoint ammunition. One is light and fast, one is heavy and slow, and the other splits the difference. As for 12 gauge, it is certainly way above your standard handgun service rounds for terminal performance.

As for my personal preference, I carry 9mm for two main reasons: higher capacity and faster follow-up shots. As others have mentioned, it’s far better to learn to put shots quickly onto a silhouette target than to only shoot a bullseye with something like a 44 magnum. While the fundamentals of accurately shooting a handgun are important, for defensive handgun use it’s better to be fast and relatively accurate. Ultimate precision doesn’t matter as much as long as you’re hitting your target - I don’t care if I hit the left ventricle of someone’s heart, I would just prefer to hit them center-of-mass.

Sorry for the rant and you may have not meant it exactly how I presented it. Thanks for bringing up the topic.

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Knock down can be acheived with a .22 if the shot is properly placed

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100% correct.
A well placed .22 is better than a miss with a .45

Magazine capacity and shot placement are more important that the made up idea of “knockdown power.” The velocity of the round factors in to the size. What you are looking for is a round with the most energy when it hits your target. Stick with 9mm with at least 15 round magazine capacity.

I have 9mm. It’s a matter of simple economics. I can afford to practice more often with 9mm ammo. I’m not in an occupation where people are out to kill me or I may be attacked by a sniper. At the close distances I figure for self defense the difference is marginal between a 9 and the larger more popular calibers. I put familiarity with my gun and accuracy above kinetic energy.

The question you are asking is like asking what kind of vehicle you should purchase. It all comes down to what you find to be the most comfortable. I have a Sig 9mm in the nightstand safe and an 870 in the bedroom closet. This combination gives me the best option in my opinion for possible home intruder type of situation. In my vehicle I carry an XDM 40 which works well for me because I love the 40 at close range. For concealment I either carry the M&P 9mm or the Pico .380.