When you think about lightweight AR’s, you usually don’t think of composite hybrids. Kaiser US is here to change that, and in a big way. Kaiser has plenty of experience in the hybrid AR market with great product success. Recently they introduced a new Titanium-Graphite composite AR15 receiver set called the X-7 Blackbird. The name pays tribute to the SR-71 Blackbird spy plane, a composite plane that was way ahead of it’s time, thus similar to the X-7 Blackbird receiver set. After having Mike, from Kaiser, on the podcast, he offered to send me one of these hot new Blackbird receiver sets for review.

Let’s talk a little about this Ti-Graphite composite. There are a lot of misnomers about composite, or plastic, receivers. Even though some of these are true, they do not apply to the Kaiser X-7 Blackbird, or any of Kaiser’s other receivers. This is because Kaiser engineered the composite receiver, so it is not just your everyday “polymer” like the others. It has more material in certain places to help with strength. But Kaiser doesn’t stop there. They wanted it to be stronger than the standard aluminum AR15 receivers. So they put titanium and anodized aluminum inserts into the places needing strength. For instance, some of these places are the threads for the buffer tube and the barrel nut threads. The Blackbird’s Ti-Graphite composite also adds in some more strength, simply because the titanium and graphite are molded into the composite. Another huge advantage to the Ti-Graphite composite is its lubricity and wear resistance. Essentially, it is so smooth that very little to no lubrication is needed. I still put some oil on the BCG, but it cycled smoothly without it. So what does this Ti-Graphite composite get you? It yields a super strong upper/lower receiver set that weighs in at 9 ounces stripped. For comparison, a standard stripped, forged AR15 lower receiver, without an upper, weighs 8.8 ounces.

Besides the Blackbird being a super lightweight receiver set, it also has some other enhancements. Up first is its textured magwell. Not only is it textured on the side, but the front as well. This texture consists of raised rectangles. For those of us that grab the magwell with your support hand, this gives you a good, no slip, grip on the Blackbird. The magwell is also beveled to help get those magazines changed quickly. Next is the fit between the upper and lower receiver. It’s tight! I have never had a matched receiver set fit like this before, in a good way. I can push the receiver pins out, hold the upper, and shake it vigorously before the two halves come apart. If you are using the Blackbird for a precision style rifle build, this fitment would be perfect and would definitely help in the accuracy department.

With the X-7 Blackbird being engineered differently, it has a few slight differences. All of them are good, just different. First, since the lower receiver is slightly wider than a standard aluminum one, at least in some spots, it can’t use standard anti-walk pins to hold the trigger in place. Standard trigger pins will work, but there is no reason to use them. Kaiser gives you their proprietary V2 anti-walk trigger pins, as well as the allen wrenches to install them. These V2 pins work for any trigger you wish to install into the Blackbird lower. It pretty much accepts any mil-spec or drop in AR trigger. The X-7 Blackbird also uses a proprietary port door on the upper receiver. As with the trigger pins, the lightweight port door assembly is also included. Most standard and ambi safeties will work with the Blackbird. I installed a Timber Creek ambi safety and it works well. Because the Blackbird is about weight, Kaiser also includes a skeletonized titanium grip screw for mounting your favorite grip. I went with the old A2 style grip, because it is one of the lighter weight grips around. The Blackbird upper receiver also does not have a forward assist. My guess is to save weight, since the forward assist isn’t always needed. The last two differences have to do with assembling the lower and upper. Instead of being able to put the rear takedown pin spring in normal, it now goes under the pistol grip, similar to the safety detent. I have zero problems with this, it's just different enough to mention. When installing a barrel and handguard onto the Blackbird, Kaiser recommends the use of a “reaction rod”. This prevents the upper receiver from being over torqued and damaged. They also only recommend 30 ft lbs of torque on the barrel nut as to not cause any unseen damage to the receiver.

A little bit about the build with the X-7 Blackbird receiver set, is in order. I wanted to try and make this build pretty light, since the Blackbird is so light to begin with. I basically took an assembled AR pistol and took it apart, that way I could use the lightweight parts on the Blackbird. These consisted of a Faxon Lightweight 10.5” pencil barrel, a Walker Defense Titanium BCG, a Dark Hour Defense Magnesium handguard, and some other miscellaneous parts. What this gave me was an AR pistol that weighed 4.2 lbs without an optic. That is with parts that one can buy everyday, no custom special parts here. If you were to put a small lightweight red dot on it, it wouldn’t weigh much more. I did install a larger red dot, a finger stop, and a light. This only brought the weight up to 5.2 pounds, which is respectable with a light. It is possible to get the Blackbird to below 4 lbs without sights, I just haven’t tried to do it yet. One could put a shorter handguard and some titanium small parts to help reduce the weight even more. I am happy with how this build turned out. When you pick it up next to my decked out 11.5” SBR, it feels like it weighs nothing.

How does it shoot? “Fantastic” would be the first word to come out of my mouth. The Ti-Graphite composite makes it so smooth. There really is barely any recoil, partly due to the Ti BCG and adjustable gas block. But It’s smoother feeling than when the same parts were in a standard aluminum receiver set. Double taps are super easy and quick to make. Essentially, this lightweight Blackbird receiver set makes an awesome place to start your lightweight AR build. I’m sure full Blackbird rifles will be available soon if building isn’t your thing.

In the end, if you are looking at a lightweight AR15 receiver set, the Kaiser Blackbird can help you out. This Ti-Graphite matched upper/lower receiver set is one of the strongest and lightest ones around. The Blackbird is way lighter than its nearest, more expensive competitor. Don’t be scared by those who say “plastic” will break, they haven’t used the Blackbird and they probably haven’t ever heard of Kaiser US either. So, if you want one of the lightest AR’s around, start with the Kaiser X-7 Blackbird receiver set and don’t look back. You’ll be getting a quality product that will perform above your expectations.