What is the Greatest Gun in the entire History of The World?

Before we can ask that question, let’s quantify “The Greatest”.  Most of the time people will refer to the Greatest as the Most Influential.  Or the Originator of some function that is thought to be important.  Or longest service. Or the most cloned and copied.  Or whatever metric puts their favorite at the top.  So what makes a gun “Great” here for this discussion?   Let’s make the criteria based on some points… Not in any order of importance:
Ergonomics:  How it fits the User and other Users.  The ease of use of the controls.
Accuracy:  Consider both Actual Accuracy, which is accuracy from a machine rest or bench rest, and Practical Accuracy which is what one can get from the gun in field conditions.  These are two separate things.
Utility:  How many uses it can be applied to, or be adapted to other uses.
Power:  Consider both the power of the individual round and capacity of the rounds in the magazine.
Range:  Not Max Range – but it’s actual practical effective range, and combine that with the Accuracy factor and you see just what you can do with the gun and how far away.

Now lets look at the guns, taking in these metrics, apply them to the INDIVIDUAL GUN and not Genealogy or History of the gun.  So for example don’t look at the MG42 and then say the Maxim is the Greatest because the MG42 was built off design evolution from the Maxim… or whatever you want to objectify as great.  If you want to quantify the Maxim on it’s own, the MG42 takes those traits and improves on them.  Lighter, less maintenance, less support required, greater reliability, etc. So based on individual merit, the MG42 is certainly the greater gun.

My knee jerk reaction would be to go with something like the Colt 1911 Government Model Pistol.  But that’s Nostalgia talking and not looking at the actual metrics set forth for the individual gun.  The Utility and Power factors point the needle to the Remington 870.  While it’s certainly adaptable for length of pull and using different shells gives you great utility, it’s limitations in Ergonomics and Range and other factors really hamstring the old girl.  Shame… Because it’s probably my favorite single firearm.  But we are not talking about Favorites.  Remember that.  We’re talking Objectively.  Which brings me to my conclusion that I can’t even being to believe that I’m about to reach here…

The Greatest Gun In The History Of The World:

The AR-15.

Just look at the results of a Google Image Search of “AR-15 Rifle“.  So many variations it boggles the mind, all built off that wonderful AR Lower Receiver.  The AR-15 can be configured and reconfigured to be The Right Tool For The Job for just about any situation that calls for a Firearm.  By pulling two pins you can change it from one caliber to the next, with rounds from .22 LR, to .50BMG, to freaking Arrows… yes, there is a Crossbow Upper for it.  You can use it as an SMG or Pistol Caliber Carbine, Main Battle Rifle, or Hunting Rifle.  There is a Muzzle Loader upper for it.  I’ve even seen a Single Shot Shotgun option for it.  You can change the parts to change the Ergos to make the gun feel great for just about any shooter.  Right handed, left handed, Ambi, it doesn’t matter.  You can put a Silencer on it and make it quieter.  You can put a Loudener on it and make it louder.  (No, seriously, someone made that.)  You can use it for Home Defense, Plinking, Competition, Hunting, Law Enforcement, and Military Actions.

The AR-15 Rifle is the Greatest Gun in The History Of The World.