Sharps Bros Livewire AR-15 lower receiver review

Written by: Buddy Murphy

This is a review of the Sharps Bros Livewire AR-15 lower receiver. Yes, these are the same guys that make lowers with skulls, warrior helmets, or other goofy things on their magazine wells. But when they get serious, they make a quality, functional piece of kit.

One of the first things you'll notice is the heavily flared mag well, which not only looks great but also makes reloads faster and more intuitive. The ambidextrous bolt release is another welcome feature, providing ease of use for both right and left-handed shooters. This particular design for a right side bolt release has the perfect amount of force needed to release the bolt. Some other receivers take too much effort to release the bolt, forcing you to move your hand off of the fire controls, like the PWS Alpha.

The right side bolt release is especially useful for me (right-handed shooter) when shooting CMP (Civilian Marksmanship Program) courses of fire. The first and last stages are single load stages. Meaning, you have an empty magazine in your rifle (or a specialty mag), you drop a round into the ejection port, close the bolt, and fire your one round. You repeat that 10 or 20 times depending on the stage. This forces you to break position between each shot. By having the bolt release on the right side, I can hold my rifle against my shoulder with my left hand, and get another round, drop it in the rifle, grip the rifle with my right hand, and close the bolt, minimizing my movement between shots.

The transition between the integrated, oversized trigger guard and the magazine well is stepped, giving it a distinct and clean look. The threaded bolt catch pin and rear takedown pin recess also add to its overall precision and durability.

As of July 2021, Livewire has undergone a significant upgrade, it is now made from a forging. The process begins with a 7075 aluminum billet, which is heated to 800 degrees and then forged into a near-final shape using a custom tool in an impressive 4100-ton press.

Post-forging, the receiver undergoes final machining on CNC machines. This reduces material costs and machine time without compromising quality. The result is a receiver that feels incredibly robust and well-finished, with every detail meticulously crafted. The anodized black finish, done to MIL-A-8625 standards, ensures durability and a sleek professional look.

Putting the lower parts in the receiver was a standard affair except for the left side bolt catch. Instead of a roll pin holding the bolt catch to the receiver, it has a small hex-head screw. This makes it much easier to attach the bolt catch than tapping in a roll pin. Also, before you attach the bolt catch, you must insert the included transfer bar. The transfer bar allows the bolt release, on the right side, to push the bottom of the bolt catch toggle (causing the top to move in towards the receiver as if you pushed it), releasing the bolt.

In summary, the Sharps Bros Livewire AR15 receiver delivers on every front; strength, precision, and aesthetics. It’s a top-tier choice for anyone looking to build or upgrade their AR15 with a receiver that truly sets itself apart from the rest. While it maintains the classic AR15 aesthetic, it brings its own unique flair and functionality to the table: like the oversized integral trigger guard, beveled magazine flare, and ambidextrous bolt release. It is fully compatible with mil-spec parts and magazines. Weighing around 8.7 ounces, it strikes a perfect balance between weight and durability.

Firearms Insider Reviews - Key Points

Claim to Fame:

AR-15 lower receiver with right side bolt release.

Target Market:

Lefties, Competition shooters, those that want ambi-everything

Features, Benefits, and Specifications of this product:

Large integrated trigger guard
Right side bolt release
Flared mag well
Forged lower
Mil-spec

What other aesthetic options or finishes are available?

Only black anodized finish

What others are saying?:

5/5 stars from Dave K. at Brownells

Absolutely the best value for the $$$

I am very impressed with this lower receiver. Everything fit perfectly. Best value for the money! All of my future builds I will use this receiver.

Link to other reviews:

The Firearm Blog

Price point:

MSRP = $136.79

Retail = $124.99 at Brownells

I need it now! Availability:

Brownells

Our Rating:

Pros:

Forged Receiver
Flared Magwell
Right side bolt release
Integrated trigger guard
Oversized trigger Guard
Mil-spec dimensions

Cons:

None

Score: 8.00 Great

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.