The Ruger AR-556 has exploded in popularity. It is possibly the best value for the money modern sporting rifle on the market today.
One of the best features of this modern sporting rifle platform is the customizability. A new lower can greatly change the aesthetics and handling of your AR-556.
Follow our guide to discover the best AR-556 lowers available today.
Comparison Chart of the Best Ruger AR-556 Lower Receivers
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Forged vs. Billet vs. Cast Lowers - Similarities & Differences
There are two main ways to manufacture lowers and it is important to know the differences.
Forged AR-15 lowers are made by hammering together two roughly formed halves while the aluminum is still hot. Later, precision machining is used to finish the product into the right shape.
This process keeps the machining, and therefore the costs, to a minimum. The hammering compresses the aluminum and aligns the metal grain into a uniform direction. This arguably makes forged lowers stronger than billet ones.
Billet lowers use a CNC machine to mill the lower from a solid block of aluminum. This is a longer and more costly process but can produce a more innovative lower.
Forged and billet lowers offer equal functionality, precision, and fit. The difference is mainly aesthetic. These days, the aluminum alloys used are such high strength that any benefit forged lowers give you in strength, is negligible. Look for 7075-T6 aluminum, but 6061-T6 is great, too.
Besides forged and billet, once in a while you run across cast lowers. These have a bad reputation, but any cast lower on the market today should be affordable and reliable. Whichever method is used, lowers from reputable manufacturers rarely, if ever, fail.
How to Spot a High-Quality Lower
Here's what to look for when you're thinking about which model to choose:
You may see manufacturers claiming that their lowers are 'mil-spec'. Some aspects of the manufacturing process may adhere to specific military specifications, such as the hard-coat finish. However, no semi-auto lower can, in its entirety, be accurately described as mil-spec.
For build material, 7075-T6 is the gold-standard in AR receivers. Keep in mind that whether a lower is forged or billet, the billet itself was originally drop-forged for increased strength. All of these will require some CNC machining in the manufacturing process, but some manufacturers cut corners, leaving mold lines along some of the edges.
A good fit means that you won't be able to see daylight through the spaces between a quality upper and your lower. Problems with quality control often manifest with the mag well. Poorly made lowers will not seat or drop mags as they should.
Recently, polymer lowers have been gaining in market share. Generally speaking, polymer firearms components are nothing to turn your nose up at. However, designs of polymer lowers probably haven't been around long enough to prove their durability.
One good way to verify the quality of a lower is to check how long a company has been around, what their warranty policy is, and what other shooters’ experiences have been when needing and using the warranty.
Review of the Best Ruger AR-556 Lower Receivers
As the MSR market continues to explode, options for lower receivers are multiplying like uncontrolled rabbits. Making sense of all the options can be a real task, but never fear, as usual, we've got you covered. Here is our list of the best AR-556 lowers.
Brownells - AR-15 M16 A1 Lower Receiver
Brownells is a huge force in firearms retail. This gives Brownells insights into what works and what people need. They also use their expertise to produce a range of their own excellent products like this lower.
This model was designed in conjunction with NoDak Spud, an all-American firearms designer. Together, they have crafted the lines of the lower to match those of the original Armalite M16A1.
This lends any build a retro-styled look. Specifically, the front takedown lug profile and the profile surrounding the receiver extension are true to the M16 look, unlike the A2 style profiles that proliferate today.
This is a forged 7075-T6 aluminum alloy lower, giving it excellent durability and strength. After forging, the lower is machined for a precise fit and finish. This is topped off with a matte black or gray anodized finish. This finish matches most modern uppers, including that of the Ruger AR-556. Although it is engraved as being made for 5.56 NATO, other calibers will work as well. This product is made in the U.S.A.
Brownells has done a great job producing this retro-styled lower. If you want to give your AR-556 an old school look, this is the way to go. The top features are the tough forged alloy construction and domestic manufacturing.
Bravo Company - AR-15 Complete Lower Receiver W/ Bcmgunfighter™ Stock
Bravo Company is no joke when it comes to combat weapons systems. This is one of the most respected companies with some of the most battle-proven products. The company was founded in 2005 by a U.S. Marine veteran.
The company's goal has always been to improve the quality of firearms in the hands of law enforcement and military personnel. As such, every little detail of this lower has been designed with attention to detail to give you the best in function and reliability.
This is a forged lower made of 7075-T6 aluminum alloy and machined to exact specifications. It is type III class 2 hard-coat anodized. This item features a number of Bravo Company's unique design features, such as their mil-spec receiver extension, PNT trigger assembly, and mod 3 pistol grip.
The M4 lock nut is staked. There are quick detach points for a sling. The hammer is un-notched and the lower is marked as suitable for use with multiple calibers. The overall weight is about 2.2 pounds. This lower is entirely made in the U.S.A.
Bravo Company is a tough company to beat for sheer quality and reliability. If you want to turn your AR-556 into the Rolls Royce of modern sporting rifles, this is the lower for you. The top features are the workmanship, reliability, and compatibility with various calibers.
Best for The Money:
DPMS - AR-15 Lower Receiver Complete With M4 Stock Assembly
Defense Procurement Manufacturing Services started out in 1985 by manufacturing parts for the military's assault rifles. Based in Minnesota, DPMS is one of the top three manufacturers of AR-15s and their components.
One great thing about this lower is that it comes complete with an M4 stock assembly, meaning all you have to do is drop in your AR-556 upper and start shooting. The stock is adjustable with six positions. It is a collapsible carbine stock constructed of high-tech impact resistant polymer.
As with all other lower receivers in our guide, this one has been forged from 7075-T6 aluminum alloy. This gives it more than enough strength for any abuse you'll ever throw at it. After forging, it is CNC machined and hard-coat anodized in accordance with military specifications.
Uniquely, on top of this, the lower is coated in Teflon for the best in scratch and wear resistance. DPMS describes the trigger group included with this lower as mil-spec. This product is made completely in the U.S.A.
This is a great lower from one of the leaders in the field, a company with a long history of big military contracts. The top features are the included adjustable stock and the Teflon coating. The value for money is very competitive, too.
4. PSA AR-15 Complete Classic Lower
Palmetto State Armory is one of America's largest distributors of firearms, firearms accessories, and components. This has given them a huge store of consumer information. They know what sells, what people want, and what products are the most reliable.
Palmetto State Armory uses this knowledge to produce its own range of firearms and firearm products. PSA's products are both affordable and highly reliable. Pretty much anything they make counts as a no-brainer option given their incredible value for money.
This is a complete lower that ships already fully assembled and ready for your Ruger AR-556 upper. It has been machined from forged 7075-T6 steel, which gives great strength and a classic look. It is type III class 2 hard-coat anodized in accordance with military specifications.
The receiver extension is also of a mil-spec diameter. This is an M4-sized lower receiver, with the corresponding stock, staked lock nut, and carbine buffer. The hammer is un-notched, and although it is functional, this is usually the first component that shooters swap out for something more high-end.
This is a hard lower to argue with. Despite the mediocre trigger, the value for money is exceptional and all other components will last a lifetime. The top feature is its 7075-T6 construction. Another benefit is that it is compatible with a wide range of calibers and other uppers, not just the AR-556.
5. PSA PA15 Complete Classic EPT A2 Lower Receiver
This is another outstanding complete lower from Palmetto State Armory. It features contemporary A2 styling. The construction method is the standard, ultra-reliable process of forging and then CNC machining from 7075-T6 aluminum alloy.
The finished product is hard-coat anodized with a type III class 2 finish. PSA calls this a 'mil-spec style A2 stock with a plastic latch' which is a contradiction, but we'll roll with it. It features a rifle-length buffer and spring.
The trigger is better than that in the PSA model mentioned above as it is PSA's enhanced polished model. All contact surfaces in the fire control group are polished. The hammer and trigger are then coated in an extra smooth nickel finish.
Palmetto State Armory rates this lower for use with multiple calibers. The hammer is un-notched to even allow use with 9mm Parabellum. If you're going for that modern-classic A2 look, this lower is for you. The stock has a very mil-spec looking dark grey color.
As noted above, Palmetto State Armory is always a safe, no-brainer option. This is a fantastic complete lower for a pretty good price. The top features are the enhanced fire control group and A2 Aesthetics. These are great, cheap products to have around, not just as an update to your AR-556.
Whether you need a specific ergonomic upgrade or just want to Gucci-up your Ruger AR-556, you will find the ideal lower on our list. Switching the old out for the new one requires no special tools or skills, but do make sure you have figured the procedure out. As always, shoot safely and have fun.