(Continued from Part 1. This concludes the article.)
Handguard and Barrel Nut
The final parts of the upper include the barrel nut and handguard. The barrel nut is used to secure your barrel to the upper and is generally included as part of your handguard. There are some handguards that don’t supply a barrel nut so you will want to check for that when purchasing your specific handguard. You will also want to match your handguard, gas tube, and barrel to make sure they all match. Standard barrel lengths are 16, 18 or 20 inches. There are various gas tube lengths such as pistol, carbine, mid-length and rifle. I won’t go over the specifics of each of these as that could be a completely separate article. It’s just important that you know what gas system you are running so that you can match your handguard to this. If you don’t match your gas tube and handguard you could buy a handguard that doesn’t cover your gas block.
I purchased the Aero Precision M5 Atlas S-One M-LOK handguard. I’m not a fan of quad rails as they are heavy, and uncomfortable. M-LOK or Keymod handguards allow you to run as many accessories all over your handguard as wanted without the bulk and sharp edges of a quadrail. The Atlas S-One is also lighter than the other options offered by Aero Precision. There are carbon fiber handguards that are extremely lightweight but also extremely expensive. As with all things I had to weigh performance vs costs and I simply could not justify the added costs of a complete carbon fiber handguard.
Upper Receiver Considerations
There is one major advantage of using an upper receiver and a handguard from the same manufacturer. That advantage is aesthetically they line up much better than if you source parts from different manufacturers. The majority of people will select the standard A2 style birdcage for their rifle. These are very affordable and do a decent job of flash suppression and recoil mitigation. I prefer a compensator due to the greater flash suppression.
Lower Receiver Components
I will now move onto the more complex and more AR-15 part compatible, lower receiver. The lower receiver consists of a bolt stop, front and rear takedown pins, magazine release, fire control group (FCG), pistol grip, buffer tube assembly, and stock. The lower receiver is, by law, the serialized firearm. Due to the hassles of buying firearms online and a desire to support local business I typically purchase a lower receiver from my local gun store. However, these can be purchased online and sometimes in multi-receiver sets which can save you money. I have found a local FFL that doesn’t charge a transfer fee, so when I do purchase online I use them to broker the deal. I would recommend doing a little research and with some luck you might find a similar situation in your area.
At this point it probably isn’t much of a surprise for me to tell you that I selected an Aero Precision lower receiver. This is due to the previously mentioned aesthetics of having your upper, lower and handguard line up. Aero Precision also has a good reputation in the LR-308 world and in the AR-15 world for that matter. They have many options of factory Cerakote components but I purchased the black components and coated them myself to my specifications. The lower receiver does have a few components that are compatible with the AR-15 I will identify those components as I list each component of the lower receiver.
The function of a bolt stop is pretty much self-explanatory this component holds your bolt open after the last round has been fired. It is not compatible with the AR-15 this is due to the LR-308 having a bigger, heavier BCG. I again opted for a standard bolt stop as there isn’t much reason to buy a fancy bolt stop in my opinion. However, I may upgrade my bolt stop by adding extended controls. These are essentially bolt-on covers that give you more surface area to actuate your bolt stop under duress. Magpul also offers what they call a BAD lever. This is a lever that extends below the trigger guard allowing for ambidextrous control of the bolt stop.
The magazine release parts are compatible with the AR-15. My experience was the standard AR-15 release was a little short. I’m planning on upgrading to an extended magazine release. This isn’t absolutely necessary but will make dropping a magazine much easier.
Front and Rear Takedown Pins
The front and rear takedown pins are also larger than their standard AR-15 counterparts. If they weren’t larger they wouldn’t reach all the way through the larger lower receiver. The takedown pins secure the upper and lower receiver together making these two halves of the rifle functional.
Pistol grips are compatible with the AR-15. This is a huge plus as most any AR-15 pistol grip could be used on your build. There are quite literally hundreds if not thousands of different AR-15 pistol grips on the market. I prefer the Magpul MOE grip but there are plenty of other great options out there.
Buffer Tube Assembly
The buffer tube assembly is made up of the buffer tube, castle nut, buffer spring and the weighted buffer itself. Each of these parts are unique to the LR-308 as they must accommodate for the recoil of a .308 cartridge and the larger size of the BCG which reciprocates through the buffer assembly. The outside diameter of the buffer tube is the same as that of an AR-15 buffer tube. This is important because it allows you to use AR-15 compatible stocks on your LR-308. The difference between the LR-308 and AR-15 buffer tube is the thickness and durability of the LR-308 buffer tube. There are different springs and weights that you can tinker with to ensure your gun will cycle a certain load, minimize recoil, or run while using a suppressor. I opted for the standard setup here as I won’t be running suppressed, don’t mind the recoil of a .308 and will be running a variety of loads through this gun.
The next component is an adjustable stock which is AR-15 compatible, another huge win for the LR-308 owner much like the pistol grip there is a wide selection of stocks out there. I opted for the Mission First Tactical Minimalist as it is one of the lighter weight options on the market. There are lighter options out there but they too are far too expensive for the budget I was on.
Fire Control Group and Safety Selector
The last component is the Fire Control Group (FCG). The FCG is made up of the trigger, hammer, their springs and the safety selector. This part gets a little confusing because there are FCG components that are AR-15 compatible and some that aren’t. However, my experience has been that most of the FCGs out there are compatible, and clearly state whether they are or are not LR-308 compatible. I’m partial to Geissele Automatics and got a good deal on one of their triggers. These are quite costly and a standard mil-spec trigger will serve adequately. It seems that over the years I have become somewhat of a trigger snob. I also decided to upgrade my safety selector and installed an ambidextrous safety selector. In my opinion this is a “must-have” to better facilitate shooting from the non-dominant side, around barricades, or in awkward situations.
LR-308 Lower Build Kits Are Available
I think it’s important to note that many companies offer a LR-308 lower build kit. This is very convenient as they ensure you have all the correct components for an LR-308 build. I found one available online that had everything (bolt stop, magazine release, takedown pins, pistol grip, safety selector) except for a FCG. This allowed me to save money by buying all these parts in a kit while still being able to upgrade my trigger choice. Midway USA has a great selection of LR-308 components made to their specifications at much lower prices than I was able to find. If it was a component I wasn’t planning on upgrading I almost always went with the Midway USA line.
Build Your Own or Buy a Complete Rifle?
You might ask yourself: “Why go through all the trouble of parting up a rifle when you could simply purchase a complete rifle off the shelf?” As I have stated throughout this article my main concern was weight. I was able to shave two to three pounds off my rifle by selecting a lightweight barrel, handguard, bolt carrier group and stock. This was very important to me as I will be carrying this rifle with me while hunting, but also because shooting heavy rifles unsupported is inconvenient and oftentimes inaccurate. There are lightweight complete rifles that can be purchased but they typically run twice that of a standard LR-308.
Assembling the rifle on my own also allowed me to upgrade the parts I found most important and use standard parts where I was willing to compromise. This kept the overall cost down. There is also something satisfying about assembling your own weapon. I know exactly how that rifle works and will have a better grasp of how to maintain and repair it because of this experience. In my opinion, everyone should learn how to completely disassemble and assemble their firearms simply to create that intimacy and familiarity with the firearm.
However, this might be something you are not comfortable doing at the moment. If you aren’t up tho that, then there are plenty of reputable manufacturers who are producing awesome weapons based on the LR-308. This might be a better option for you. Whether you buy a complete rifle or part one up on your own I would highly recommend the extra firepower that the .308 Winchester brings to the table.