Lower: Understanding the Nuances of The AR-10

Updated 7/27/2021 Their simplicity of upgrade seems to be the most appealing aspect. You want an AR rifle that can be used in close quarters? An AR can do this. What about a long-range system that can clip a fly’s wings at 500 yards? Eugene Stoner’s brilliant brainchild is a great choice. It’s almost a no-brainer to upgrade an AR-15. The civilian rifle has benefited greatly from its military cousin, the M-16, which offers a wide range of upgrades that can be used for almost any application. The rifle is now standardized, so almost every aftermarket part will fit your rifle regardless of whether it’s a Colt Smith & Wesson or CMMG. The AR-10, the big brother of black-rifle families, is a little more complicated. Armalite makes a 7.62 rifle. The older version uses modified M14 magazines. This has made it more difficult to build and shop for larger-caliber ARs. Manufacturers have made it possible for users to design their own AR-10s, but there are some limitations on how they can be upgraded or put together. It’s not standardized so it requires additional consideration to get the AR-10 to work properly. While it’s not rocket science, it isn’t as easy as picking and choosing like the AR-15. Once you understand the basics, you can open the door to many new calibers, including.308 Win. and 6.5 Creedmoor. You can expect a rifle that is as flexible and adaptable to its brother as it is to your little brother. However, once you understand the basics, you will be able to unlock a whole new world of calibers -.308 Win., 6.5 Creedmoor, and.270 Win. AR-10 Lower Receiver. Other than calibers, receivers (upper or lower) are what define the AR-10. They will guide you in building, upgrading, and maintaining your rifle. Even if you are planning to buy one off the shelf, it is important to consider the rifle’s heart. You will eventually need to replace a component. Your choice of receiver can make or break your life. Bottom: Palmetto State Armory DPSM lower receiver, note the angular rear cut. The vast majority of AR-10s use one of two patterns of receivers: DPMS, LR-308 or ArmaLite (which is by definition the AR-10). Rock River was a major player in the early days. However, its LAR-308 design didn’t see the same aftermarket profusion. Today, the AR-10 is all the rage, and manufacturers have gone beyond standardizing, unlike the AR-15. There are many different patterns available, some specialized and not compatible with parts from the same company. These patterns are highly proprietary so we’ll stick to what you’ll find in stores and through AR parts dealers. ArmaLite’s rear cut is angled, while the DPMS lower’s rear cut is elliptical. Upper receivers are able to work with their own type for most of the time. An ArmaLite lower won’t accept a DPMS pattern, but the inverse will. This configuration is not recommended. This configuration will result in a functional rifle but large gaps between the receivers that invite dirt into the internal components. The gap is at the level of the face when the firearm is fired, making it difficult to see if a case has ever burst. There are other differences between the patterns. These are mainly related to parts. We’ll get to those in another post when we dive into AR-10 upper receivers. Another notable difference is magazine compatibility. DPMS held a clear advantage in this area, using modern magazines based upon the original waffle-pattern. These magazines were produced by Magpul and D&H Industries. They were also inexpensive and easily available. ArmaLite, however, made their own magazines (there were a few others) based on the M14. This was changed in the last decade. ArmaLite introduced its Series A receivers (Series A is the traditional receiver design). These receivers are compatible with industry-standard magazines that use the waffle pattern. The company’s catalog now focuses on the newer pattern. Although Series B AR-10s can be ordered, there are a few manufacturers that are part of each team. However, the DPMS may have more. Fulton Armory is one example. Palmetto State Armory, CMMG and Fulton Armory all use Gen I DPMS designs. ArmaLite, Knight’s Armament, and Noveske are just a few examples. Not all parts are compatible. But not all. The trigger, the last component, is particularly nice. It opens up a floodgate of top-shelf choices. Notice the larger hammer. It will fit in your.308. It’s at home in your.308. They’re more robust, especially their hammers. Jard’s single-stage and two-stage.308 triggers, and Timney’s Drop-In.308 Drop In are just two examples. They have more meat on the bones. They are praised for their durability and reliability by some shooters. This is a controversial point, as there are many cross-purpose AR-15/10 triggers that work in the larger-caliber rifles without a hitch. The limited number of designs makes it more difficult to build a new rifle. It is easier for a manufacturer not to specify all compatibility details and offer a complete rifle. Emails complaining that “my gun doesn’t work with XYZ part …”” are common. However, it is possible to still build a rifle using the most popular patterns, starting with the foundation. Aero Precision and good ol’ Armalite are two good places to start. The Aero M5 is a great option for first-timers in an LR-308 lower pattern. Aero components are well-made and affordable with precise specs. The M5 is a reliable rifle that will last a lifetime. It is a solid investment because it comes with a few extra bells and whistles. One of its most distinctive features is a polymer-tipped set screws that can take the sound of a rifle. It’s an LR-308 design, which makes it much easier to build the lower due to the many aftermarket parts that are available. Armalite AR-10 A Series
You don’t know where else to build an AR-10. This lower will give you Armalite markings and a nice receiver. The Armalite lower, which is an A Series design, offers greater magazine compatibility. It has a touch of tradition that goes back to the origin of the rifle. B Series receivers are not always readily available. This is bad news for throwback builders. Although it’s not as simple as building or shopping for an AR-15, the process of decoding the AR-10 isn’t as difficult. Understanding the differences between the AR-10 lower receivers can be a great starting point. It also helps you understand the compatibility of the parts and then shop for them accordingly. This requires extensive research about the rifle you want to build. Once you have decided on the AR-10 manufacturer, be sure to ask them about the exact specifications and compatibility of the parts. It’s not enough to look at the geometry of the receiver to confirm it works, especially after being spoiled by the Mil-Spec AR-15. Learning the intricacies of AR-10 is worth it. You’ll have more caliber options and a rifle that is ready to go the extra mile. Mastering an extremely unique weapon system is also a benefit. Target grids and bullseye sizes can be downloaded in MOA. Perfect for long-range shooting! Get free targets