The T.A.R. 21 is an Israeli bullpup assault rifle chambered for 5.56x45mm NATO ammunition with a selective fire system. The name \"T.A.R. 21\" stands for \"Tavor Assault Rifle - 21st Century\". The T.A.R. 21 advanced model Tavor 2 was selected as the future assault rifle of the Israel Defense Forces, and within the next few years it will become the standard infantry weapon.The T.A.R. 21 uses a bullpup design, as seen with the French FAMAS, the British SA80, Austrian Steyr AUG, Singaporean SAR-21, Iranian Khaybar KH2002, Chinese Norinco QBZ-95, and Belgian FN F2000. Bullpup rifles are configured in a layout in which the bolt carrier group is placed behind the pistol grip; this shortens the overall length but does not sacrifice barrel length. In theory, the T.A.R. 21 provides carbine length, but rifle muzzle velocity. The bullpup design is also used to minimize the silhouette of Israeli soldiers and to maximize effectiveness in turning corners in urban warfare.The T.A.R. 21 has ejection ports on both sides of the rifle so it can easily be reconfigured for right or left-handed shooters. However, this process requires partial disassembly, so it can not be quickly configured while the rifle is in use.The T.A.R. 21 design is based on advanced ergonomics and composite materials in order to produce a more comfortable and reliable rifle. The T.A.R. 21 is waterproof and lightweight. It also includes an advanced red-dot reflex sight and can be mounted with different scopes, night vision systems and other electronic devices.The T.A.R. 21 accepts standard STANAG NATO magazines. It can also be mounted with the M203 grenade launcher. Its ambidextrous fire mode selector above the pistol grip has a semi-automatic mode, burst mode, and a fully automatic mode.After initial testing within Israel Defence Forces\' infantry training units, the T.A.R. 21 was distributed to Givati Brigade troops during Operation Defensive Shield. Seen by some as \"futuristic\", the bullpup layout has actually been around since the 1940s when the United Kingdom developed the EM-1 and the EM-2 assault rifles. Initial results have been favorable - the T.A.R. 21 was found to be significantly more accurate and reliable (as well as more comfortable) than the M4 Carbine during extensive field testing - but the battle proven and widely issued M16 and its variants will remain in service for some time to come; their unit purchase price is about one third that of the T.A.R. 21. Originally there were some problems with fine sand getting into the Tavor\'s chamber, but reportedly, numerous adjustments were made and the problem has been corrected.