The evolution of the standard-issue Taiwanese Army service rifle that began with the T65 of 1976 and evolved into the T86 of 2000 has culminated in the T91 of 2003. The T65 proved the first Taiwanese indigenous design initiative based on the successful Armalite/M16 family line and incorporated changes to suit the local military. The T86 was developed to help modernized the qualities of the T65 though production proved limiting (under 5,000 units). However, the T86 program helped to further the new line of assault rifles taking hold in the Taiwanese military as the T91. The T91 was developed in 2002 and quickly placed into production in 2003. Production is ongoing as of this writing (2013) to which over 140,000 units have been dispersed. As with the previous marks, production of T91 rifles is handled by the 205th Armory of Combined Service Forces.
Externally, the T91 follows the same M16-inspired design that was forged in the original T65. The receiver retains the same general appearance, incorporating the integral pistol grip, trigger unit and magazine hold as well as the T-style charging handle along the upper receiver rear. One of the key differences in the T91 is the installation of a six-position adjustable telescoping stock. There is also greater support for tactical gear which can make use of the included rails along the forend. The barrel is shorter than in the original T65 for a more compact profile (the collapsible buttstock aids in an even smaller profile). Like the T86 before it, the T91 makes use of a four-position selector switch for safety, single-shot, burst and full-automatic fire modes. The included iron sights are adjustable and optics supported along the upper receiver (in place of the standard-issue carrying handle). The T91 is fed from a standard 30-round curved box magazine and supports various STANAG types as well. There is noted support for an underslung single-shot 40mm grenade launcher.
The T91 is chambered for the 5.56x45mm NATO cartridge and fires from a gas-operated rotating bolt function. Rate of fire is higher than in preceding designs, spanning 800 to 850 rounds per minute. Overall weight is 3.17 kilograms unloaded with a running length of 880mm. This length is reduced to 800mm with the stock collapsed completely. The barrel measures in at 406mm. Muzzle velocity is 975 meters per second with an effective range out to 600 meters in ideal conditions. Maximum range is accordingly further.
As of this writing (2013), the T91 is designated as the formal replacement for all preceding Taiwanese service rifle marks. The weapon has also proven an export success with sales to Bosnia and Herzegovina, Indonesia, India, Jordan, Kuwait and the United Arab Emirates. The T91 is a solid alternative to operators wanting an M16-style NATO-friendly weapon over those competing global designs inspired by the Soviet AK-47. The T91 compares favorably to the M16A2 model.