The Myth of "Knock Down Power".

The Myth of "Knock Down Power".

In a nutshell there is none if your pistol doesn't start in "4" or better.  As well, then it is more of a psychological reaction than a physical reaction to being shot IF you do not score a hit in a critical area.

Newton's law of physics says for every action there is an equal and opposite reaction.  So, if the gun doesn't knock you down when you shoot it, it won't knock someone down when the bullet hits them.  There are other factors of course. 

A 9mm has been accused of being a poor defense caliber.  I even made such accusations at one time.  NOW, I think 9mm is a fine defense caliber and is perfect for small concealable handguns.  It is fast, and has minimal recoil (except when fired from a small handgun like a Kel-tec PF-9 or Taurus 709 Slim).  It also has NO knock down power.  Nor does a 38spl, or a 357 mag, or a 40 s&w, or a 380 acp or, or, or... 

Now, hold up.  I know many of you reading this want to disagree with me on the 357.  And, I will give you that it has more "knock down power" than any other caliber listed above, but it suffers from a small projectile and a high velocity.  Meaning, it is likely to not expend all of its kinetic energy on the target, but rather pass through.  With a proper defense round, it could stay in target, or leave with minimal force left to impart.  But it still suffers from a small projectile, which means a small primary wound channel.  As well, while it travels fast for a pistol bullet, it travels too slow to create a significant secondary wound channel.

The 45 acp loaded to travel over 950 ft/sec is your best option for knock down.  Even it will only provide limited push in the "opposite" direction on your target.  But, bullet size, type of bullet and projectile speed will make sure that all of the energy it has to impart on a target is transmitted.  Again, remember, if you want to approximate what your target would feel when hit with a bullet... just shoot your firearm.  What you feel is a good approximation. 

What makes most targets "go down" is either a hit in a critical area or the psychological effects of being shot... perceived pain, fear, etc.  So what does this mean for the average shooter.  It means don't be an average shooter.  Be proficient with your chosen personal defense firearm(s).  It means be able to hit what you aim at.  It means be able to put multiple rounds on target.  It means Hollywood isn't real and no ones arm will be blown off and no one will be sent backwards through plate glass.  Physics... It's the LAW.