Building Your First AR-15 - A Beginners Guide
A complete beginner guide to choosing parts for your first AR-15 RifleOk! You're here because you're likely a DIY'er and want to learn how to build an AR15. If you can build it, you will better understand how it operates and how to repair it; we think that's important! This down-and-dirty guide is not a complete tutorial but an introduction to the components required to build a functioning and versatile 'first build.' At the end of this article, we share a lazy-mans way to a semi-custom AR15, so be sure to check it out!
The Assemblies
A complete AR15 has two major assemblies, referred to as a "Complete Barreled Upper" and "Complete Lower," and are connected by the 'takedown' and 'pivot' pins at the front and rear of the AR15 receiver. We're going to break down the various components by their major assemblies.
Complete Barreled Upper
Complete Lower
Sub Components of Complete Lower Assembly
Here's a breakdown of the lower parts and pieces that you will want to become familiar with before you get started.
Lower Receiver **
My go-to for nearly every build is an Aero Precision M4E1 Lower Receiver. They are high quality, precision machined, and offer added conveniences you'll appreciate during assembly. Instead of using traditional roll pins and requiring special punches to attach certain parts, these use threaded pins. As a new builder, it will save you much frustration and reduce the risk of accidentally damaging the finish.** Note: The Bureau of Alcohol, Tobacco, Firearms and Explosives regulates who can obtain this component by requiring us (as a Federal Firearms Licensee (FFL)) to "transfer" the lower receiver to another FFL in your local area. Your local FFL requires you to complete ATF Form 4473 and undergo a background check through the National Instant Criminal Background Check System (NICS). The process is not complicated, and we've written an informative guide to assist and educate first-time buyers.
Lower Parts Kit (LPK)
The LPK features your safety selector, mag and bolt release, and other small parts required to complete your lower receiver. Some LPKs include a component-style mil-spec trigger, and some don't. Some LPKs include a grip, and some do not. We recommend buying the Aero Precision M4E1 MOE Lower Parts Kit, including the trigger (Fire Control Group (FCG)) and Magpul MOE grip. The MOE grip features a clever storage compartment to tuck away paperwork, small tools, optic batteries, or whatever you dream up. Alternatively, you could take a slightly different path by purchasing an Aero Precision LPK without the trigger and any of our drop-in triggers for AR15.
Note: If you take my recommendation on the M4E1 Lower Receiver, you'll want to ensure to purchase an LPK designed for an M4E1 as it includes the threaded pins instead of the mil-spec pins included with most other LPKs.
Trigger
If you took one of the two paths I recommended above, your trigger is taken care of. The mil-spec component trigger (also referred to as a Fire Control Group (FCG)) is quite possibly the most daunting task for a new builder. Watch a few installation tutorials on the web, and you'll figure it out after a few tries. The one-piece drop-in trigger alternative I mentioned above is the quickest way to a customized trigger and typically offers a much better shooting experience. The trigger is a personalized component, each having a different feel. I recommend you look at these entry-level drop-in triggers: TriggerTech AR15 Duty Trigger, the Rise Armament RAVE , the Timney Impact, or the ELF SE. All the trigger brands we retail are top-quality, with excellent technical support should there ever be a problem.
Buffer Kits
Buffer kits include the receiver extension, buffer spring, buffer, castle nut, and end plate. These five components are included in all of our Buffer Kits. For your first build, I recommend no other than a Carbine Buffer Kit. This allows you to use a collapsible stock and is the most widely used buffer setup in the AR15. There are other types of buffers, but they're outside the scope of this guide.
Stock
To complete your lower, you'll want a stock. I'm a big fan of the Magpul MOE-SL. It's designed with comfort in mind, is light on weight, is simple to handle, and offers a sturdy and reliable lockup. While stock choice often boils down to personal taste, I'm confident you'll find the MOE-SL appealing. Magpul truly nailed it with these stocks, and I'm more than pleased to outfit any carbine buffer tube with them. If that's not your preference, you can browse all of our stocks that are compatible with a carbine buffer kit.
A Quick Plug
A quick plug about the Arm or Ally brand of products: Manufacturers offer unbranded products made to the exact specifications but without being marked as an "X" brand. Our house-brand products are unbranded, 100% made in the USA by the same industry-leading manufacturers. When selling branded products, we must adhere to a set of pricing rules stating we cannot sell a particular item for less than a set price. Our house-branded products are not bound by these rules, allowing us to offer the same high-quality product at a more favorable price to our customers.Sub Components of the Complete Upper Assembly
Now for the Upper parts, you're almost up to speed!
Upper Receiver
The upper receiver is an easy choice now that the lower is sorted. I recommend the Aero Precision M4E1 Threaded Assembled Upper Receiver as it perfectly matches the M4E1 lower and works well with standard handguards. (Hint: You can also buy these receivers as a set and save a few bucks). Where this is an "assembled" upper, meaning the dust cover and forward assist is already installed, you do not need an Upper Parts Kit. If you already have an upper parts kit on hand or simply want to learn how to install these parts, you can also purchase the stripped version of the M4E1 Threaded Upper Receiver.
Calibers and Barrels
Regarding barrels, there's a lot of debate about the length, caliber, and material by which they're made. My recommendation is based on dependability & performance, longevity of use, and the the availability of ammo and reloading components (another hobby you should consider!). Without question, I recommend a very classic 16" 5.56 NATO (which can also shoot .223 Remington). We carry several, though if I had to pick one, it's the Ballistic Advantage 5.56 NATO 16" Mid-Length barrel with a Tactical Govt. profile. This is a proven caliber with a very reliable and smooth shooting gas profile in a popular tactical profile. Moreover, this barrel comes with a sub-MOA accuracy guarantee from the manufacturer. If you are on a budget, go with our house-branded equivalent to this.
With this barrel, go ahead and get yourself a gas block and gas tube. A standard .750 gas block and mid-length gas tube are all you need. If you have some extra to spend, I highly recommend upgrading your gas block to a superlative arms direct impingement adjustable block. This is the best of the best, very adjustable to help with fine-tuning your gas system. As of this writing, if you purchase a Superlative Arms gas block, your entire order of parts will ship for free.
Muzzle Device
The muzzle device is another one based on personal preference. Much of the muzzle device comes down to its appearance, though some can improve your shooting experience through recoil reduction. The standard option is a very inexpensive A2 Style Flash Hider and crush washer. If you want something with a little recoil reduction (at the expense of increased noise), check out the VG6 Epsilon 556. Be sure to check your local laws when it comes to ordering flash hiders and muzzle brakes. If you're still undecided, go ahead and get the A2 Style device. It's an inexpensive stopgap until you find one you like.
Handguards
Moving forward, our next step involves selecting a handguard. I suggest opting for a handguard that extends as far as possible without going beyond the beginning of your muzzle threads. Since we're working with a 16” barrel, a 15” handguard is the ideal choice. My recommendation is the ATLAS R-ONE 15" handguard. This option is my preferred go-to due to its sleek design, lightweight build, and ample space for attaching necessary accessories. If that's not your style, you can view all of our AR15 handguards here.
Bolt Carrier Group
There are many styles of Bolt Carrier Groups (BCG) on the market. Flashy coatings are the newest fad. The thing to remember here is your BCG is the heart of your rifle. It will receive as much, or more wear and tear as your barrel over time. My recommendation is again, based on dependability & performance, the ability to source replacement parts, and in this case, the warranty! If I had to pick one, it's the Toolcraft 5.56 NATO Bolt Carrier Group in either Black Nitride or Diamond Like Carbon (DLC) finish. Neither of these finishes is a coating, so they cannot flake if applied incorrectly. I favor the DLC finish over the Nitride, though either will serve you well for thousands of rounds. Moreover, Toolcraft has the industry's best warranty - for Life!
Charging Handle
The final puzzle piece, the charging handle. For a beginner build, keep things simple and get yourself a standard mil-spec charging handle. They're cheap, and honestly, they worked just fine for all of my military patrols. If you really need something a little fancier, some charging handles are offered in various colors, and add some practicality with wider handles. Have a look at the Aero Precision BREACH Charging Handles or even Radian Raptors are a nice option. See all of our AR15 Charging Handles here. As with the muzzle device, if you're undecided, get a mil-spec handle. They're simple to swap out later.So Are You Ready?!
Now if all of this sounds overwhelming, or you just don't have the time for a 100% custom build of your own, there's still hope. Aero Precision has a wide selection of Complete Uppers and Complete Lowers which easily fit together. Plus there is a certain peace of mind knowing a professional armorer assembled the build and is covered under warranty. If you decide to take this route, you'll want to ensure to get a charging handle and bolt carrier group, as most of the complete uppers do not come with these components (a few of the more expensive ones do include these items - check the descriptions for specific details)
One last money-saving tip - we offer Aero Precision Builder's Sets which include an Upper Receiver, Lower Receiver, and Handguard in one package. Instead of buying them separately, buy them together and save a few bucks in the process.
Boom! You now have all of the parts needed for a rifle build. When you're ready to accessorize, there are all sorts to think about, from optics, lights, backup sights, slings, bipods, and all sorts of gadgets, the options are endless.
