Wolf Arms A1 Piston Upper

By Oleg Volk

Since Taiwanese defense strongly depends on the alliance with America, it made sense to keep equipment as compatible as possible. Adopted in 2003, T91 piston upper fits any AR15 or M16 lower. The A1 upper, so marked by the importer Wolf Arms, is a faithful adaptation of the Taiwanese army rifle, missing only the bayonet lug. Almost all parts are made in Taiwan, with barrels finished in the US to comply with import regulation. Unlike most of the piston upper  designs for AR-15, T91 is neither front heavy, nor overly complicated. It's even affordable at $599 list price.

Having tried a wide variety of supposed improvements on the conventional AR-15, I wanted to find out just how well it would handle and perform. The charging handle is the standard AR part, but the rifle does not use a forward assist button. The forend is proprietary to the upper, resembling the old American M16A1 clamshell. It proved very effective at insulating the support hand from the barrel heat even with heavy volume of fire. Wolf A1 upper uses a 1-in-7" twist, nitrided hammer-forged 16-inch barrel, same as its military counterpart. The A2-like flash hider also has porting further back to act as a compensator. The front sight tower is integral to the upper. Any AR-15-compatible rear sight fits the receiver Picatinny rail. 

It turns out that the proof by performance is compelling. First, the A1 upper is shockingly accurate for a basic field grade carbine. The best groups were with Remington Hog Hammer 62gr—1.1MOA. Federal Gold Match 69gr was a close second at 1.2MOA. 55gr American Eagle ball spread was 2.2MOA. With minimal recoil and great accuracy—much helped by the 1.8-10x US Optics scope—the rifle was a pleasure to shoot. The muzzle blast was unremarkable despite the obviously effective compensator. At this point, I've fired about 500 rounds of varied ammunition fed from several types of magazines, and no malfunctions of any type were encountered. I only shot brass-cased ammunition, but James Grant shot quite a bit of steel-cased 5.56mm through it with no issues. For users who have select fire capable lowers, the A1 upper is full-auto compatible.

The upper contains a piston return spring, while the bolt carrier is returned into battery by the standard bugger spring in the stock. Turning and pulling on a substantial retainer pin out of the sight tower allows removal of the gas piston and captured spring. The short stroke system uses the return spring in the upper only for the resetting of the piston, while the bolt and carrier are replaced into battery by the regular AR buffer. Because of that, the A1 cannot be fired with a folded stock.

Not having done any destructive testing, I can only refer to the records of the military acceptance trials that resulted in T91 adoption to various degrees by Indonesia, India, UAE, Jordan, Kuwait, Bosnia and Herzegovina. The Taiwanese Army fully converted to T91 a decade ago.

This article first appeared in Small Arms Review V21N5 (June 2017)
and was posted online on April 21, 2017


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