The M4 CARBINE IS BETTER THAN THE M16.
No one will give you an M4 rifle/carbine for free.
M4 is the carbine- shorter barrel
The Colt M4 Carbine .22 is a replica of the real M4 but in .22 caliber.
There is an M4 carbine in Call of Duty: Modern Warfare 2.
The M4 carbine is a shorter and lighter variant of the M16A2 assault rifle. The M4 is a 5.56×45mm NATO, air-cooled, direct impingement gas-operated, magazine-fed carbine. It has a 14.5 in barrel and is 33 inches long.. It weighs 6.5 lbs.
The M4 carbine has a muzzle velocity of 2,970fps(884m/s).
5.56mm
While the M4 Carbine is intended to fire a 5.56x45mm NATO round that is distinct from the .223 Remington, both are centerfire cartridges. So yes, the M4 Carbine is a centerfire rifle.
A carbine is simply a shorter version of the long gun. If the long gun was rifled, the carbine version would also be rifled. Examples of well known carbines with rifled barrels include the M1 Carbine of WW 2 and the M4 carbine version of the M16.
Perhaps they just forgot to add the "A1" to the nomenclature in CoD4. But yes, you are correct - the standard M4 carbine has the three round burst feature, while the M4A1 and the Canadian variant of the M4 (the C8) have full auto capability.
The M4 carbine was adopted into service with the United States armed forces in 1994.