What Are Lover Receivers?
AR-15 lower receivers contain about 20% of the assault rifle’s components and are technically considered firearms because they house the firing mechanisms. Lower receivers connect to upper receivers to make a complete AR-15 rifle, and you can either buy them completed or stripped down to assemble on your own. One important thing to remember is that the AR-15 lower receiver is one of the most regulated parts of a MSR rifle. This is where you’ll find the firearm’s serial number, and when purchasing one, you’ll be required to take a standard FBI background check.
At Hinterland Outfitters, you’ll find lower receivers from all your favorite brands, including some of the most popular lower receiver manufacturers:
- Smith & Wesson
Anatomy of a Lower Receiver
Often call the “lower” for short, an AR-15 lower receiver contains the pistol grip, buffer tube, bolt catch, buttstock, magazine well and release, trigger group, disconnector, hammer and safety selector:
- Trigger Groups: The trigger group of an AR-15 lower is vitally important to the function of the rifle—you can’t fire with a trigger. The trigger group consists of the trigger, hammer and other necessary housing components. When choosing a trigger group or assembling one from various parts, you want to make sure you choose one that has a comfortable pull weight, or the amount of pull it takes to squeeze the trigger back. Many enjoy using a light trigger pull to increase accuracy and firing rate, but a light trigger can lead to negligent discharge (ND). For this reason, law enforcement and the military use heavier trigger pulls, usually 8-9 pounds. A “light” trigger pull is usually something under 4 pounds.
- Buffer Tube/Buffer: Sometimes referred to as a lower receiver extension assembly, the buffer tube assembly is a spring that slows down the backwards movement of the bolt in order to absorb some of the felt recoil and push the bolt back into the place when chambering a new round. This has a number of benefits. For starters, you’ll be able to shoot longer and more accurately with less recoil. Additionally, it helps ensure the integrity of the rifle by slowing down some of the faster action and containing it better. If putting your own lower together, make sure your buffer tube and stock have the same specifications because buffer tubes come in two sizes: mil-spec and commercial-spec.
- Buttstock: How your rifle rests into your shoulder is integral to a comfortable shooting experience. The buttstock connects to the firing mechanisms of your assault rifle, and usually, it slides right onto the buffer tube assembly. When searching for the perfect buttstock, you’ll find that there are two major categories to choose from: fixed and collapsible. Fixed stocks tend to be stronger and can help to balance out heavier front ends, while collapsible buttstocks allow you to adjust the length so you can find the perfect fit.
- Magazine: Lower receivers contain the magazine well where your magazines slide into, as well as the magazine release, which allows you to eject the magazine to refill or swap it out. Magazines hold the rifle’s ammunition and vary in size. It’s important to understand your state’s laws regarding magazines because they can vary from state to state.
- Pistol Grip: Since your trigger hand has the final word when firing, you need a good grip, and there is a wide array of grips to choose from. Make sure you have a pistol grip that feels comfortable when wielding your assault rifle. The more comfortable and firm you grip, the better your shooting experience will be.
- Lower Parts Kit: The modular design of the AR-15 is what draws many gun enthusiasts to it, as they love the ability to customize and assemble their own rifle from specifically chosen parts. A lower parts kit gives you everything you need to assemble your own lower receiver the way you want it.
When browsing AR-15 lower receivers, you’ll find they come in two major types: stripped and complete. A complete lower receiver- includes everything you need to plug and play. These lowers include the trigger group, buffer tube, butt stock, pistol grip, operating levers and magazine. A stripped lower receiver- only includes the shell of the receiver. With a stripped lower, you’ll need to install all the various parts of the lower receiver yourself. Many gun enthusiasts will prefer a stripped lower because it gives them endless customization options.
While shopping for your new AR-15 lower receiver, you’ll run into some terms referring to the lowers’ manufacturing processes. One important thing to note is that aluminum alloys are the go-to for lower receivers due to their lightweight strength and ability to resist corrosion. However, you’ll find some differences between the ways in which the lowers are crafted.
- Aluminum Alloys: There are two major aluminum alloys used with lower receivers: 6061-T6 and 7075-T6. 7075-T6 is a stronger alloy, while 6061-T6 is more resistant to corrosion. When it comes to AR-15s, most of the high pressures and stress are within the upper receiver, so having an extra strong lower may not be necessary.
- Cast Aluminum: A casted lower receiver is made by pouring molten aluminum into a mold, and once it is solidified, the lower is finished on a Computer Numerical Control (CNC) machine. Due to their manufacturing process, cast lowers tend to be the most economical choice.
- Billet Aluminum: A billet lower receiver is crafted from a solid block of aluminum alloy. This “bar stock” is then fed into a CNC machine, which then carves, or billets, excess aluminum away until the final shape and intricate design of the lower is achieved. Many gun owners like billet lowers because they tend to have very clean and aesthetically pleasing designs.
- Forged Aluminum: Forged lowers are created using a forging process of compressive forces. The aluminum is hammered and pressed into an initial shape, then finished on a CNC machine. Most metallurgists agree that forged aluminum is stronger than cast or billet.
Buying Lower Receivers from Hinterland Outfitters
If you’re new to AR-15s, it may be best to purchase a complete lower that will save you the headache of assembling one from various parts. However, here at Hinterland Outfitters, you’ll find everything you need to build your perfectly customized and personal AR-15 lower. Don’t hesitate to contact us and speak to one of our knowledgeable customer service representatives, who will help you choose the best AR lower parts and kits.