Editing Carbine (section)

===Contemporary military forces===
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| image1 = AUG A1 508mm 04.jpg
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| caption1 = [[Steyr AUG]] ''rifle'' ({{convert|508|mm|in|1|abbr=on}} barrel)
| image2 = AUG A1 407mm 03.jpg
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| caption2 = Steyr AUG ''carbine'' ({{convert|407|mm|in|1|abbr=on}} barrel). Carbine conversion is achieved by changing to a shorter barrel.
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[[File:OH-58D 2.jpg|thumb|right|Two M4 carbines stowed ahead of the [[flight instrument]] panel of a US Army [[Bell OH-58 Kiowa|OH-58D]] reconnaissance helicopter, over Iraq in 2004]]

In 1994, the U.S. had adopted the [[M4 carbine]], a derivative of the M16 family which fired the same 5.56mm cartridge but was lighter and shorter (in overall length and barrel length), resulting in marginally reduced range and power, although offering better mobility and lighter weight to offset the weight of equipment and armor that a modern soldier has to carry.

In spite of the benefits of the modern carbine, many armies are experiencing a certain backlash against the universal equipping of soldiers with carbines and lighter rifles in general, and are equipping selected soldiers, usually designated marksmen, with higher-powered rifles. Another problem comes from the loss of muzzle velocity caused by the shorter barrel, which when coupled with the typical small, lightweight bullets, causes effectiveness to be diminished; a 5.56mm gets its lethality from its high velocity, and when fired from the {{convert|14.5|in|adj=on}} M4 carbine, its power, penetration, and range are diminished. Thus, there has been a move towards adopting a slightly more powerful cartridge tailored for high performance from both long and short barrels. The U.S. has experimented with a new, slightly larger and heavier caliber such as the [[6.5mm Grendel]] or [[6.8mm Remington SPC]], which are heavier and thus retain more effectiveness at lower muzzle velocities.

While the U.S. Army adopted the M4 carbine in 1994, the [[U.S. Marine Corps]] retained their {{convert|20|in|adj=on}} barrel M16A4 rifles long afterwards, citing the increased range and effectiveness over the carbine version; officers were required to carry an M4 carbine rather than an M9 pistol, as Army officers do. Because the Marine Corps emphasizes "every Marine a rifleman", the lighter carbine was considered a suitable compromise between a rifle and a pistol. Marines with restricted mobility such as vehicle operators, or a greater need for mobility such as squad leaders, were issued M4 carbines. In 2015, the Marine Corps approved the M4 carbine for standard issue to front-line Marines, replacing the M16A4 rifle. The rifles are issued to support troops while the carbines go to the front-line Marines, in a reversal of the traditional roles of "rifles for the front line, carbines for the rear".