The M16 was invented by famos gun designer Eugene Stoner. The M16 uses the 5.56x45mm NATO round. It uses 20-30 round detachable box magazines. It is curently being phased out by the US Army in favor of the Mk16 and Mk17 FN SCAR weapons.
The M16 was introduced to the US Army in 1970 during Operation Salvo. During Operation Salvo the US soldiers armed with M16 massacured NVA troops with the deadly 5.56x45mm round.
After Operation Salvo the US Army began issuing its soldiers M16A1s. The M16A1 Began to Jam and malfunction in battle due to the mud and the lack of spectalized cleaning kits. Also the US soldiers where wasting ammunition by using so called spray and pray tactics. From then on the Newer M16A1s didnt have a fully autamatic fire mode and replacing it with a 3-round birst setting.
M16A1 to the A4Edit
After the vietnam war US troops where issued cleaning kits with there rifles as standard with the M16A2, A more reliable model of the A1 but featured only semi and 3-rounde burst settings.
Then the A3 was introduced featuring a fully autamatic fire mode. It looked identacal to the A2.
The M16A4 is a modified version of the A2 the only diference is the abilty to fit optics and an array of attachments compatable with the M4A1 carbine.
The M16 A1-A3 only where able to use M203 renade launchers. The M16A4 can feature a variety of optics, grenade launchers and laser designaters.