Variation on a Theme: Building a Piston-Driven Taiwanese T91 Clone

While most of my builds are AR-based and often US military clones, this one is a little different. It is AR/M16-based, but it’s a piston-driven system that uses a lot of proprietary parts. This is another clone, but this time it’s a clone of the Taiwanese T91 service rifle. It took me a while to get this one right, but it was worth the effort.

Wolf Performance Arms Upper

Wolf Performance Arms offers complete T91 uppers in 12.5 inch and 16 inch versions. They’re based on Taiwan’s T91 service rifle and use the T91 style upper and piston system. T91 uppers are not compatible with regular AR uppers. They have a steel piston guide attached to the front of the receiver to accommodate the T91 piston rod.  They do not have a forward assist, and the brass deflector is not as pronounced as the C7/A2 Brunton bump. The uppers have a full length MIL-STD-1913 Picatinny rail on the top and use a standard AR/M16 ejection port cover. The Wolf uppers come with a huge “Wolf A1” logo emblazoned on the left side of the receiver, which I’m not a fan of.

Wolf uses a heavier barrel pattern than the Taiwanese military rifles, and the gas block assembly lacks the bayonet lug and forward rails of the military guns. The front sight base is largely the same as the military guns although the front sight post is a different height so that it works with most standard AR rear sights. Handguards are issue two piece style with heat shields. Wolf has shipped these with variety of muzzle devices and mine came with one that was not the same as the issue one.

I picked up my upper from Atlantic Firearms and it was around $525 at the time. They’ve been out of stock for a while but they do pop up here and there.

Bad Attitude Dept Lower

The T91’s lower is a basic M16A1 style, although the military version has a 4 position fire control assembly. S – safe, 1 – semi-automatic, 3 – three-round burst, and A – automatic.  Both T91 Tactical and Bad Attitude Department offer properly marked lowers for T91 builds. BAD initially offered A2 pattern lowers with T91 markings, since that was the only forgings they were working with at the time. That’s what I went with initially. It was considerably less than the T91 Tactical lowers, and I’ve used a lot of BAD lowers on builds and have always been happy with them. I figured since the Wolf upper wasn’t pure military T91 anyway and A2 vs A1 profile didn’t matter that much. The BAD lowers was $109.95 for a stripped lower versus $220 for the A1 profile from T91 Tactical.

The T91 uses a proprietary buffer tube, castle nut, and collapsible buttstock, as well as its own unique pistol grip. You can use standard AR parts for these, but if you want the T91 look you need the correct ones. They’re available from both Linemount and T91 Tactical. I got parts from both for my build depending who had what in stock at the time. You can use a standard AR carbine buffer spring and buffer in the T91 tube. For lower parts I used a standard AR-15 lower parts kit. You can find actual T91 lower parts kits, but they’re all full auto parts as far as I know. I didn’t want to mess with that. Visually they look the same externally as far as I can see in pics of real T91’s, so I was good with that.

Initial Build and First Rebuild

My initial build was the stock Wolf A1 upper on the BAD A2 lower. I added a a gray East German surplus sling I had laying around with an old HK forward sling snap clip. I slapped on a Magpul back up sight and an old Sightmark Wolverine red dot that I had on hand. I also picked up the original T91 style 30 round magazine. These are STANAG compatible but have indicator holes for the top 2-15 rounds, and two protrusions on each side to avoid over insertion.

 

Somewhere along the way I added a T91 sling in the Taiwanese digicam pattern, and T91 bayonet that I picked up from a vendor off of Ebay from Taiwan. The bayonet was supposedly a style that was tested and manufactured in some quantity, but then never adopted. Whatever its story is, its a well made made bayonet with some neat markings that go with the rifle well. The only problem was that it wouldn’t actually mount on the Wolf upper. The 16 inch barrel doesn’t provide the proper standoff distance, and it lacks a the bayonet lug.

At the range, the gun ran great. It was smooth to shoot, and reliable. In fact it ran so well that I started getting the itch to make it a more proper clone build. The Big Wolf A1 billboard on the upper bugged me, and the barrel length and profile bugged me. Issue T91’s used a 14.5  inch barrel and had a front sight base (FSB) that would accept a bayonet. I thought about getting my barrel cut down and the muzzle device pinned and welded, and then replacing the FSB with a military one. I realized by the time I did that I may as well just get a new barrel in the correct lighter barrel profile.

T91 Tactical had correct mil spec barrels and I ended up picking one of those up. The new barrels were chrome lined and properly manganese phosphate finished too. I also picked up the correct flash hider. The T91 barrel uses a unique barrel nut, so I grabbed a T91 barrel wrench while I was at it.

Since I was pulling the barrel anyway I took advantage of having the upper stripped and spayed it with Norrell’s Moly Resin in “Black SOCOM Colt Flat” color to cover over the big Wolf logo. You can still see it if you look close, but it’s much less obvious. I did the re-barrel myself and had the flash hider pinned and welded by CDS Arms, my local SOT dealer, to meet the ATF’s arbitrary 16 inch barrel requirement. The new set up was much closer to a real T91 so I pulled my existing sights and added a flip up BiaoTac T91 Folding Rear Sight.

The Final Build

I was honestly pretty happy with this build. It handled great, and looked correct unless you really looked and saw the coated over Wolf logo and A2 profile lower. I was calling it close enough. That was until SHOT Show this year. I spoke with Joel Edwards, the owner of Bad Attitude Department. We had talked a bit prior to this and he confirmed that he was getting correct A1 forgings soon, and that the T91 would be one of the first models he’d make. This was big news for the collectors community as correct A1 profile lowers were tough to come by. H&R has their lowers, which are fine as long as you want H&R markings on them. I’ve used a bunch on builds. You couldn’t get other markings though. Joel’s lowers were being forged to original Colt spec, using a set of original Colt blueprints. I signed up to get a T91 upper right there and anxiously awaited it’s arrival.

 

Joel also let me know that Linemount had a great deal on T91 uppers without the Wolf Logo, and I ordered one of those that night. It’s a nice upper, but doesn’t come with the steel piston guide. Joel moved his from the Wolf upper to the Linemount one, but I haven’t done that yet. T91 Tactical says they have the part on order, although they don’t have an ETA on it. I was told they’ll be on the website when they’re available. I’m holding out a for a while to swap uppers because I’d like to put the Wolf upper back together with the original barrel since I’ll have a barrel and upper sitting around either way. Alternatively, I’ve been trying to get my father in law, who’s a tool and die maker, to make me a guide. He doesn’t seem very enthused by the project though.

Between waiting on the forgings, and a shop move from Albany, Missouri to Lenoir, North Carolina it took a bit for the A1 lowers to ship. I got my T91 A1 forging receiver in July though, and BAD is up and running on those and a bunch of other A1 pattern lowers now. I also got an A1 profile GM Hydramatic lower and finished my GM clone build correctly. You can get customs done as well, which BAD has always been great with. My M16K and my later N23A1 lowers were custom’s with custom engraving from them. He’s done a few other oddball custom for me as well.

As soon as I got my new T91 lower I swapped out my lower parts and reassembled my rifle. I had ordered a different T91 rear sight in the meantime as well. I may eventually run optics on this build although I haven’t decided what. From looking at pics of real T91’s in service it looks like Taiwan has used a variety of optics both imported and domestic. In the meantime, I liked the look of the T91 Simple Rear Sight. I may even end up trying a carry handle sight at some point if I decide not to add optics.

In the end I spent a ton on this build between starting with a Wolf complete upper, rebuilding most of it, and then swapping lowers. Still, I’m glad I did it. My final build is a pretty accurate clone of the Taiwanese t91 issue rifle. It’s a handy build, with a distinctive look, and a reliable piston action. The 14.5-inch military profile barrel makes for a much lighter weight rifle than the 16-inch heavy profile Wolf barrel, too. It also takes a bayonet now, which is how military clones should be.