Best Ambidextrous AR-15 Lower Receivers & Conversions [Tested]

Can you name a single platform as adaptable as the AR-15? 

I certainly can’t.

The AR-15 started as a relatively simple rifle, but back in the 1960s it was a piece of space-age technology.

As times changed so did the rifle. It keeps changing and evolving and most modern rifles are taking their design cues from the AR-15. 

That’s the good thing about mass production, the products require little craftsmanship, and that allows them to be adaptable en-mass.

With the AR-15, the actual legal firearm portion of the firearm is the lower receiver. 

Like every other part of the AR-15, the lower has evolved.

One of the larger evolutions has been the creation of ambidextrous lowers.

The AR-15 has been more modular than most, but the standard receiver layout has always gone more or less the same way. It also favored righties. 

We’ve gathered some of our favorites at a variety of price points and from our favorite manufacturers. 

Summary of Our Top Picks

1. 

   Editor's Pick

   Aero Precision Ambi AR-15 Lower

   Staff favorite, easy to mount parts to

   $209 at Aero Precision Jump to Details
2. 

   Best Billet Lower

   Rainier Arms AR-15 Ultramatch Mod 3 Billet Ambi Lower & Upper Set

   Good quality, flared magwell

   $434 at Rainier Arms Jump to Details
3. 

   Best Fully Ambi Model

   Lewis Machine & Tool AR-15 MARS-L Stripped Ambidextrous Lower

   Fully ambi, perfect for lefties

   $287 at Primary Arms Jump to Details
4. 

   Most Durable

   Knights Armament SR-15 IWS Complete Lower Receiver

   Durable and reliable

   $865 at Brownells Jump to Details
5. 

   Best Mid-Tier

   Radian Weapons R-15 Ambidextrous Lower

   Solid mid-tier lower, fully ambi

   $408 at Brownells Jump to Details

Why an Ambidextrous Lower? 

The most obvious answer for using an ambidextrous lower is that you are left-handed. It gives your left-handed shooter the ability to control their rifle like a right-handed shooter. 

A major advantage of the AR-15 system is that due to the brass defector and the design of the rifle, even wrong-handed shooters using a right-hand ejection AR-15 won’t get brass in their face.

There is no need to learn an odd or different manual of arms to control your weapon. An ambidextrous lower will grant you the ability to easily manipulate your rifle.

Beyond accommodating lefties, we can also point out the fact that any shooter, regardless of their dominant side, can better control their weapon in a variety of situations. 

Modern shooting techniques have seen shooters learning how to shoot better when accommodating for cover. Part of this is learning to shoot around cover and switching shoulders to do so.

Sometimes it makes sense to switch shoulder to fire around an obstacle and to make the most of your cover. 

An ambidextrous lower allows you to establish good cover regardless of your dominant shoulder and still maintain total control over your weapon. Speaking of cover and odd shooting positions an ambidextrous lower simply offers you more options to get the job done. 

If you are in a state like California and you are looking to do a featureless build, then an ambi lower can make handling the rifle much easier due to the different ergonomics attached to featureless builds.

Ambi controls, especially ambi safety levers, are better designed for featureless builds. 

Downsides? 

Everything has a downside, right? Ambidextrous lowers have a couple, at least two I can think of. 

The first is going to be the price associated with ambi lowers.

They are certainly a lot more expensive than your standard lower. We live in a day and age where even extremely high-quality lowers have dropped a lot in price.

Ambi lowers haven’t dropped much in price and are quite expensive. 

More than that they are often built by high-end companies who tend to already be on the expensive side. 

The only other thing close to a downside is the fact you are going to have to learn how to utilize the ambidextrous controls. You’ll have to retrain to make the most of these controls, but training means more shooting so I’m not sure how exactly that is a bad thing. 

Best Ambidextrous AR-15 Lowers

1. Aero Precision AR-15 Ambi Lower 

The Aero Precision brand is the most affordable of ambidextrous lower receivers. Aero as a company is one of my favorites when I’m trying to find a quality AR component that won’t bend me over a barrel price-wise.

The Aero Precision ambi lower allows you to easily mount an ambidextrous safety and an ambi magazine release. 

The safety selector channel is set for a short-throw safety and Aero suggests the Battle Arms Development Ambidextrous Safety Selector switch.

This reduces the amount of throw and allows you to switch between safe and semi quite rapidly with very little effort.

It’s compatible with all standard uppers and is made with the same quality you expect from Aero Precision. 

What’s your take on the Aero?

2. Rainier Arms Ultramatch Billet Ambi Lower & Upper Set

A slight step up in the cool factor when it comes to ambi lowers is the Rainier Arms Ultramatch. It’s not a forged upper, but a billet cut upper and lower set.

This gives it sharper and cleaner lines and a sleeker overall appearance. 

There is a slight step in price versus the Aero model but there is an undeniable cool factor when it comes to billet lowers.

The Ultramatch billet lower gives you the ability to install any ambi lower parts you choose, including both standard and 45-degree short throw safeties.

The lower sports a flared mag well which will make reloads slightly faster and more intuitive. It’s a nice touch that I appreciate. Additionally, there is a tensioning screw that will allow for better upper and lower fit, but if you purchase a quality upper the fit will probably be solid regardless. 

Like most billet uppers it also has an integral trigger guard and is made from 7075 aluminum. It’s finished with black anodization and is perfect for all your lefty needs. 

3. Lewis Machine and Tool MARS-L Lower Receiver 

Lewis Machine and Tool is a well-respected and well-renowned AR-15 manufacturer that produces some extremely awesome AR-15s. They are always on the cutting edge of weapon development and the MARS-L lower is a testament to that development. 

The MARS-L lower receiver is a fully ambidextrous lower that offers an ambidextrous selector, magazine release, and of course an ambi bolt catch and release. Its magazine and bolt catch components are machined into the lower itself.

The MARS-L comes in both stripped and complete variants, but even the stripped variants come with the ambi components installed. Its ambi controls are nearly identical to a standard AR.

The bolt releases are both vertical — separated slightly by placing the right-side bolt release slightly rearward. 

The magazine release is placed slightly lower on the left side of the lower. This is about close as you can get to standard AR controls on an ambidextrous lower receiver.

This is one of the most ergonomic ambidextrous lowers out there. It’s expensive, but also well made. 

4. Knight’s Armament SR-15 IWS 

Bombproof, that’s probably the best way to describe Knight’s Armament rifles and accessories. Knight’s is a legend in the business and has been making a wide variety of weapons for the special op’s community for decades. 

As a company, they’ve pushed the AR series forward time and time again. Knight’s is still a relatively small, independent company that continues to innovate.

Their lowers are outstanding and as far as I know, all they produce is ambi lowers. 

The SR 15 series are ambidextrous lowers built to some of the most demanding specs imaginable. If you go the Knight’s route for your ambidextrous lower I’d go with a complete lower versus a stripped lower. 

If you do with a complete lower you get all Knight’s Armament lower parts. This includes the Knight’s ambi safety selector, magazine release, and bolt release.

The Knight’s Armament lower receiver positions the magazine release almost identically on each side and the bolt release on the right side runs vertically instead of horizontally. The entire set-up has set the standard for ambi lower receivers. 

Knight’s provides some of the highest levels of quality control possible. Knight’s ambi lowers are far from cheap, but they are likely the best you can possibly obtain. They are forged lowers and black anodized for that mil-spec look.       

5. Radian Weapons R-15 Ambidextrous Lower

Bringing a fully ambi lower to the table, the Radian R-15 is another model the PPT staff dig.

It offers up a Talon Ambidextrous Safety Selector, left-side magazine release, and right-side bolt release to deliver options to those that need them.

Billet-machined from 7075-T6 aluminum, the R-15 is a reliable lower that brings a nice touch to any AR-15 build.

What If I Want to Mod My Regular Lower?

Maybe you already have an AR built and ready and you love it. You’ve already spent the money to build a great lower receiver but you want to make it ambidextrous.

The good news is that this is an option. Admittedly these options are not as intuitive as a true ambidextrous lower but they do add a good degree of ambidextrous design to any old standard MIL-SPEC lower. 

Take note, I said MIL-Spec lower. There are lots of different crazy types of lowers out there and some of these parts may not fit in polymer lowers, custom-built billet lowers, etc. 

Best AR-15 Ambi Conversion Parts

1. Norgon Mag Release 

The Norgon mag release is the original, often copied, ambidextrous magazine release. It’s easy to install and allows for quick and easy mag swaps with either hand. One side is your normal AR magazine release, and this does allow you to use something crazy like a Battle Arms Development enhanced mag release. 

Installation is easy and is not much different than a standard AR-15 magazine release. Once installed you’re ready to rock and roll with either hand and you’ll have no problems as a lefty.  

2. Knights Armament Ambi Magazine Release 

The Knight’s ambi magazine release is a bit different than the Norgon. It extends a second arm rearward on the left side of the receiver. This second arm has a textured pad that is used to drop the magazine. It allows you to easily manipulate the weapon with any hand and in any situation. 

The Knight’s system is an all-in-one kit that replaces your standard magazine release in any standard AR-15 lower receiver. It’s quick and easy to install and before you know you’ll have an ambidextrous magazine release. 

3. Battle Arms Development Safety 

Ambidextrous safeties are all the rage and are the easiest ambidextrous additions to any AR-15. The Battle Arms Development or BAD Safeties come in a variety of configurations and colors. This includes the standard and lightweight models. 

The BAD safeties are all ambidextrous and very easy to install. They install like an average selector switch and then you attach the other side to the main mount with an Allen key. Don’t forget to add Loc-Tite to keep everything good. 

4. Knights Armament Ambidextrous Safety Kit 

The BAD safeties are great but a lot of people dislike the fact that left-handed safety portions are smaller than the normal safety lever.

Some prefer some, some don’t. If you want two full-sized safety selectors go with Knight’s Armament. 

This Ambi safety kit comes with a short and a long lever so you still run a shorter lever if you so choose. It drops in and installs very easily. The levers are textured and made of steel.

The Knight’s Armament drop-in safety kit is a quick and easy way to convert your lower to an ambi safety. 

5. Troy Ambidextrous Bolt Release

The bolt release isn’t as simple as switching out the magazine release and safety. You can machine the receiver and install a PDQ device, or you can install the Troy ambi bolt release.

The Troy ambi bolt release replaces the standard bolt release and then pushes a lever into the trigger guard. 

A simple press of this lever shoots the bolt closed. The lever sits inside the trigger guard and makes it easy for either hand to accentuate the bolt release. A simple movement of your trigger finger makes it easy to send the bolt home. 

Final Thoughts

While there are plenty of complete ambi rifles on the market, it’s still nice to have options — especially if you’re building your own AR-15.

Whether you choose Knight’s Armament, Radian, or Aero, you’re in good hands.

Are ambi lowers worth it to you? Let us know below! For more awesome ways of improving your AR-15, take a look at the Best AR-15 Upgrades!