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 M16 assault rifle has a greater range than the M4 carbine as a result of its 20-inch barrel, compared with 14.5 for the M4. The M16 can hit an area target out to 800 meters while the M4 is effective to 600 meters.
580mm, or 22.83 inches. Rather long barrel for a .22 rifle.
By definition, a carbine is a short rifle. The standard M-16 has a 20" barrel, while the M-4 has a 16" barrel. A number of US Rifles have had carbine versions, with the notable exceptions being the M-1903 and the Rifle, .30 M-1.
The M4 is capable of automatic fire, the AR 15 is not
A rifle
M4 is the carbine- shorter barrel
Aside from the obvious differences, such as the collapsible buttstock and shorter barrel (14.5 inches vs. 20 inches), there are some more subtle ones. The M4 has a higher Front Sight Base to compensate for the shorter sight distance, the M4 uses a different buffer and buffer spring than the M16, the M4 has an indentation in the barrel to accommodate the M203 grenade launcher mount developed for the M4 (government law enforcement M4s typically have a barrel without this indentation), and the M4 has a longer set of feed ramps which also extend into the lower receiver itself.
No one will give you an M4 rifle/carbine for free.
AR-15 = Semi-Auto civilian rifle M4 = Select Fire Military rifle
Most airsoft AUG inner barrels, are equivalent to an m4's inner barrel due to the bullpup design.
Basically they are the same. But a long Barrel and a long shoulder stock make a gun a Rifle.