Thank you ' Robust Rascals ' for your submittal.
Top to Bottom: M16A1, M16A2, M4A1, M16A4 U.S. Assault Rifle ...
Over 10 Million Manufactured.
Originally introduced for combat during the Vietnam War.
In actual Military use since 1963 -Present
Limited production began in 1959 with testing.
Designed by - Eugene Stoner and L. James Sullivan.
Fitst Manufacturer - Colt Defense. (Note - Colt purchased the manufacturing rights of the AR15 from ArmaLite).
Several other U.S. manufacturers followed - Harrington Richardson Firearms; General Motors; U.S. Ordnance.
There were also Non-U.S. Manufacturers - Daewoo; FNH; Elisco.
Weight - 7.18 Lbs (unloaded).
Overall Length - 39.5 Inches.
Barrel Length - 20 Inches.
Ammo Caliber - 5.56x45mm NATO
Rate of Fire - 12 to 15 rounds/min
Magazine - 20 or 30 Rounds; Optional 100 round drum.
Action - Air cooled, gas operated.
Variations and modifications are numerous, among them the ability to add a Bayonet for the U.S. Marines and a M203 Grenade Launcher.
Capable of also firing a .223 Round.
In 2010 The U.S. began phasing out the M16 for the M4 Carbine, shown below ...