The Taiwanese T91 is one of the lesser-known combat rifles in service today. Loosely based on the AR-15, the T91 rifle family incorporates a short-stroke piston into its action.
A special version of the T91 upper receiver is being imported to the United States by Wolf Performance Arms (WPA), the sister company of the popular American ammunition company, Wolf Performance Ammunition (Wolf Performance Ammunition also goes by WPA, but for the sake of avoiding confusion in this article, I will only refer to the arms company as WPA). While the receivers and furniture on the original T91 look very similar to that of the AR-15, they are not compatible. However, the WOLF A1 upper receiver kit is built from a specially modified T91 upper receiver that is compatible with a standard AR-15 lower receiver and firing group.
The T91 is the latest model in a family of piston-driven, AR-15 style rifles and carbines developed by the Taiwanese Ministry of Defense’s (MOD) 205th Joint Services Arsenal. The 205th Arsenal can trace its lineage back to the famous Hanyang Arsenal, founded in 1891 to modernize the then-imperial army from the last Chinese dynasty. Built with the help of Germany, the Hanyang Arsenal produced the Gewehr 88 as the Hanyang 88 rifle and later, variants of the Mauser 98 rifles. Then, the Manchu dynasty was overthrown and replaced by the Chinese Republic in 1911.
During World War II, when the invading Japanese forces were approaching the area in which it was located, the Hanyang Arsenal was dismantled and moved to a safer area near the new wartime Chinese capital of Chongqing, where it was re-established as a handful of smaller arsenals. The modern-day 205th Arsenal is descended from one of those Hanyang offshoots and was relocated to Taiwan after the nationalist government lost the civil war to the Chinese Communists in 1949.
In the post-war period, the Taiwanese military (which, today, is officially called the Republic of China Army [ROCA]), replaced its Mauser rifles with the American M1 Garand. In 1966, the U.S. Springfield Armory sold the tooling and technical package of the M14 rifle to the Taiwanese Ministry of Defense.
The Taiwanese production of the M14 rifle, designated as the T57, was adopted in 1969 to replace the M1 Garand that was in service. The naming convention of all ROCA weapons systems, including small arms, is based on the year the weapon was adopted. Interestingly, the “T” in the weapon designation is short for “type” in English, instead of in Chinese. The year number is in the Chinese Republic year. Year 1 starts in 1912, after the overthrow of the last imperial dynasty in 1911.
Just as the U.S. military with the M14, it didn’t take long after adopting the T57 for the Taiwanese military to look for a lighter and less-expensive rifle design. In the late 1960s and early 1970s, a small number of M16s was imported for use by special units in the ROCA.
The Taiwanese MOD liked the high-velocity small caliber in 5.56x45mm and the lighter weight of the weapon. However, the licensing deal with Colt fell through, and the Taiwanese military was also concerned with the reliability of the direct gas impingement system used in the M16. Instead, it decided to develop its own 5.56mm-caliber rifle with a combination of the basic layout of the M16, along with an AR-18-inspired short-stroke piston system.
T65 AND T65K1
The result of that development was the T65, which was launched in 1977. The original T65 was nothing short of a catastrophe. The gas piston system was buggy, and the biggest issue was related to the construction of the gun.
With no experience in aluminum gun parts and no help from Colt, the T65’s receivers were made from cast aluminum. The fit was not good, and the cast aluminum receivers were painted black, which didn’t last long as a finish. Without the surface-hardening offered by the anodizing process, the aluminum was easily dinged up or even completely broken with hard physical impact.
Most of the T65 rifles in service were the much-improved T65K1 model that came out a few years later. It featured forged receivers and an anodized finish, plus an added internal aluminum heat shield for the handguard.
The most significant differences between the T65/T65K1 and the M16—aside from the short-stroke gas piston system— are the lack of a forward assist, the absence of a carrying handle and the AR-18-style handguard that is made from a more durable polymer. Other added improvements to the T65K1 version were the Israeli Galil-style tritium night sights and additional nonslip ribs along the handguard.
The T65K1 handguard is solidly held in place by a threaded screw instead of a D-ring. The trigger pack on the Taiwanese T65 is also very different from that of the M16, because it’s a completely self-contained unit like that of the aftermarket drop-in trigger packs available for the AR-15.
The T65K2, which was first introduced in 1987, was basically an “M16A2-ized” model with a number of improvements. One of the major improvements was the cold hammer-forged barrel with a 1:7-inch twist rate for firing the SS109/M885 long-range, 62-grain, 5.56x45mm cartridge (designated as the T74 cartridge) in conjunction with the licensed production of the Belgian FN Minimi (M249) light machine gun chambers for the same ammo.
Some of the other M16A2 features that made it into the development of the T65K2 were the carrying handle, rounded cross-section handguard, birdcage compensator and the select-fire, three-round burst setting. Unlike the M16A2, the T65K2 didn’t remove the full-automatic setting; it just added a fourth setting. This was most likely because the short-stroke gas piston operating system kept the cyclic rate of fire at less than 700 rpm.
The T65K2’s handguard was changed to the A2-style top and bottom halves, and the retaining screw was replaced by a captive pushpin. While the two halves are interchangeable, the top piece doesn’t have cooling ventilation holes near the front, due to field reports of dirt and sand getting into the gas piston and connecting rod, causing the weapon to malfunction.
Eventually, the tritium sights were removed, because they were found to be of limited value in the dark at anything beyond pistol range. The T65K2 was issued with two types of muzzle devices: one that looks just like the M16’s A2 birdcage with enclosed bottom and a longer version with a shorter birdcage and a multi-hole pepperbox section behind it.
The new metal magazine has four stop tabs, and the inside of the T65K2’s magazine well features four matching cutouts that were designed to prevent over-inserting the magazine during reloading.
In service, the T65K2 was proven to be a reliable and accurate combat rifle in the hands of the Jordanian military and a few other smaller foreign users.
T86 AND T91
The Taiwanese T86 airborne carbine is an accumulation of what was supposed to be the T65K3 and the efforts to make a shorter-carbine model inspired by the American M4 carbine.
The T86 features a new, self-contained gas piston system, with everything held inside of a steel tube—which fixes the issue of sand and dirt getting into the piston of the T65’s gas system.
The barrel is shortened to 14.8 inches and includes a muzzle device, making the overall length 16 inches. The polymer A1-length fixed stock is replaced with a collapsible stock, and a new trapezoid-shaped handguard design has been added.
The known users of the T86 are the Jordanian military and the Taiwanese Coast Guard, because they found the shortened carbine to be handy in operating on a maritime vessel. Interestingly, the Special Forces units in the Taiwanese military actually acquired the Colt M4 carbine for its lighter weight and lower cost. By then, whatever ROCA airborne units still existed were “airborne” in name only and were no bigger than company size. They were happy to stay with the full-sized T65K2.
The T91 was developed in 2003, and it’s essentially a flattop version of the T86. A short Picatinny rail section was also added to the new, one-piece front sight base (FSB)/gas block unit. Initially, the T91 attracted a few new foreign military users, including the UAE, Indonesia and Kuwait. According to early field tests conducted by the Jordanian military, it was shown that the T91 matched the AK47 in reliability in the sandy desert environment. Even Saudi Arabia, India and the Philippines had acquired small numbers of the T91 for their paramilitary forces.
By the late 2000s, about 100,000 T91s were ordered by the ROCA to equip its mechanized infantry, armor units and military police. In 2011, the Taiwanese parliament allotted additional defense funding to purchase an additional 300,000 T91 rifles to replace all the T65 variants and even the few remaining T57s still in service with the Taiwanese military.
WOLF A1 UPPER
Wolf Performance Arms (WPA) approached the Taiwanese 205th Arsenal, which produces the 55-grain, brass-cased .223 Rem. ammo (imported as the WPA Gold) for WPA’s sister company, Wolf Performance Ammunition. This was an effort to import the 205th Arsenal-made T91 as an upper to be sold as Wolf Performance Arms A1.
While they look alike, the T91’s receivers are proprietary and not drop-in compatible with that of AR-15. However, it is easy enough to make them work with some modifications.
The biggest issue was the ATF importation restriction that prevented importation of the barrel. The solution for that was to import everything as parts and assemble it in the WPA facility in Tennessee. While WPA did try to bring in the original chromelined, hammer-forged barrels, it did not succeed in getting approval from ATF. Instead, it was imported as an uncontoured and unfinished hammer-forged, 16-inch barrel blank with rifling. Then once in the United States, it was CNC-machined to the appropriate external contour and given a nitride finish.
I was one of the lucky ones to obtain an early WOLF A1 writer’s sample for field testing. My WOLF A1 sample came with a 16.5-inch barrel and two-piece FSB/gas block—which is different than the one-piece unit with the short 1913 rail underneath on the Taiwanese military T91.
The two-piece FSB/gas block found on the WOLF A1 is a carryover from the T86, except with the bayonet lug removed. The only T91s that I see with the same FSB/gas block are the Taiwanese police and coast guard model: They have no need to mount a bayonet or an under-barrel grenade launcher (the Taiwanese 40mm UBGL mounts to the FSB/gas block Picatinny rail section on the military model). The WOLF A1 upper kit retails for $599, with a complete bolt carrier group and charging handle included.
At the range, the WOLF A1 upper’s accuracy was better than I expected—but keeping in mind that the T91 is a combat rifle with a gas-piston action and non-free-float barrel, the accuracy is more adequate for its intended role. The WPA Gold 55-grain .223 Rem. ammo used is produced by the same 205th Arsenal that also makes the T91 rifle for the Taiwanese military and supplies the components for the WOLF A1 upper.
- CALIBER: 5.56 NATO
- ACTION TYPE: Short-stroke gas piston (proprietary Rapid Clean, one-piece system)
- RECEIVER: T91 receiver modified for compatibility with AR15 lower receiver
- BARREL: 16.5 inches; hammer forged; 1:7-inch twist; nitride finish
- HANDGUARDS: Authentic T91
- MAGAZINE: Accepts STANAG-compatible mags
- SIGHTS: Two-piece FS/gas block
- INCLUDES: Authentic T91 charging handle and bolt carrier group
- MSRP: $599
Editor’s note: A version of this article first appeared in the March 2018 print issue of Gun World Magazine.