Nobody. M16 is a military nomenclature specific to variants of the AR-15 rifle in 5.56x45. The rifle which the M16 was derived from - the Armalite AR-10 - was in 7.62x51 and does not have an "M" series nomenclature from the US Military, as it was never adopted into service by the US military.
As for civilian variants of the AR platform, there are many manufacturers - Knight's Armament, DPMS, Rock River, Bushmaster, just to name a few.
the standard m16 shoots the 5.56mm, but it can be converted to shoot 9mm, 7.62mm, even .308
kiss my butt
A M16 cost about $2000.00
With enough money, yes.
you don't.
M16
The M16 was invented @ 1960
The M16 and the M4 are the US designations for the AR-15 pattern of rifles.
I believe that Colt has the government contract to produce the M16 for the US military.
1960
Yes, along with the carbine version of the M16, the M4.
the m16 uses 5.56 caliber ammo