Custom-Built AR-15s Will Always Beat Stock Rifles: Here's How To Build One

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2024 marked my 10th anniversary in the competitive shooting sports world. I started with stock firearms for just about every shooting sport, except for a couple where I borrowed guns from more veteran shooters. I ran a stock Glock 17 (with stock sights), a Daniel Defense DDM4 V7 (with flip-up iron sights), and a Stoeger M3000 with no extended tube, and these firearms got me hooked on 3 Gun competitions. As I progressed in shooting sports, I began to tinker with my stock guns to make minor adjustments to the controls or functionality and give me a more competitive edge. Once I maxed out the performance of each of these firearms, I moved to more customized guns and eventually began building my rifles.

Building a competition AR-15 rifle that is accurate and soft-shooting will give you the most advantage over competitors. Some components have a more practical purpose, while others are more aesthetically pleasing. I recommend dedicating most of your budget to parts that will make shooting the gun more pleasurable by decreasing reticle movement and muzzle rise. Anything that doesn’t contribute to the gun’s performance is secondary. The parts that affect felt recoil and accuracy are the barrel, gas block, buffer system, and muzzle brake. The parts that are less performance-based and more about fitting the gun to you and its purpose are the handguard, controls, and stock. The Bolt Carrier Group (BCG) lands somewhere in the middle, both practical and performance related.

Can’t Skip the Right Tools

You can’t just use any tools to build a rifle. A vise of some sort is a necessity, and if you can swing for it, the Real Avid Master Gun Vise allows you to lock your gun into place and rotate it in different positions so you don’t have to play contortionist when installing parts. There are torque specifications for the barrel nut and muzzle brake, and you need to be able to set the foot-pound and not just guess. You’ll also need an upper and lower vice block to put in your vice and hold each in place to torque down these parts. The Armorer’s Master Kit has all the necessary items to build a rifle to proper specs. I also use the Smart-Torq & Driver Master Set to install the safety selectors, grip, and any other set screws.

Building a rifle tailored for a specific purpose and customized to you can be an intimate experience. There are likely millions of manufacturers producing AR-15 components, barrels, triggers, stocks, and more, which can be overwhelming but also means there’s something for everyone. Let’s dive into one of my most recent custom builds and what I look for when building an AR-15 for competition.

Receiver Set

I recommend starting by choosing a receiver set. It’s best to select a receiver set from one manufacturer to ensure the upper and lower receivers fit together properly. Mixing upper and lower receivers from different brands does not guarantee compatibility. This is also where the rifle’s purpose comes into play. For my most recent build, I wanted a super lightweight AR-15 that I could loan to my female students, allowing them to use it all day without getting as fatigued as they would with a heavier rifle. The Bully Arms Skeletonized Receiver Set could not have been more perfect for this build. The other reason I chose this receiver set is that it’s built more for competition than self-defense, as it isn’t designed to use a forward assist or ejection port cover. Every little ounce counts, and this cuts down the weight; fewer parts mean less maintenance. I can also count on one hand the number of times I’ve used a forward assist in my life.

Barrel Selection

Think of the barrel as the heart and soul of your rifle. Depending on the brand and where the barrels are sourced, some stock rifles are equipped with a quality barrel off the shelf. I recommend budgeting for the best barrel to give you the best accuracy. I have built different rifles for specific competitions, and the two main decision factors were barrel length and weight. I prefer a 16-inch barrel to anything else, so I don’t have to SBR it or pin and weld a muzzle device, but the longer length, in addition to the muzzle device, isn’t always the best choice. I have also used a 17.7-inch barrel but opted for a fluted profile to decrease the weight while getting the best accuracy due to the added length.

Sticking with the lightweight rifle concept, my latest build features a 14.5-inch X2 Dev Group Trident Barrel in the mid-length gas system configuration. With any barrel shorter than 16 inches, you must pin and weld the muzzle device to make it 16+ inches or register the lower receiver as a short-barreled rifle and pay a tax stamp. This barrel's profile includes specially timed flutes that act as opposing I-beams, blending structural integrity with reduced mass and maintaining optimal barrel harmonics.

Another thing to note about a quality barrel is that you must pair it with quality ammunition. The X2 Dev Group barrel shoots sub-MOA with match-grade 75-grain and 77-grain .223 ammunition. Using poor-quality ammunition will get you poor results. This barrel is chambered in .223 Wylde, which allows for the safe use of .223 Remington and 5.56 NATO ammunition. A .223 chambered barrel is incompatible with the use of 5.56 ammunition, as the higher pressure of these rounds can lead to catastrophic failure, damage to the barrel, and damage to the chamber. Make sure that no matter what barrel you use, it’s compatible with the ammunition you plan to use.

Gas Tube Length, Gas Blocks, and Installation

Without getting too technical, gas tube length and the gas block can affect felt recoil significantly. The length of your barrel and compatibility dictates gas tube length. Generally, the rifle-length gas system makes a rifle shoot softer than carbine or mid-length gas systems. An adjustable gas block vs. a fixed gas block can allow you to tune your rifle to your ammunition and set the amount of gas you want to enter the gas system. If you plan to suppress your rifle, an adjustable gas block is the way to go.

I opted for the X2 low-profile fixed gas block, which you can select with the Trident Barrel. Installing a gas block is not as easy as it might seem. The hole in the barrel must align with the hole in the gas block so gas can flow down the gas tube and into the BCG. Gas blocks don’t always sit against the shoulder of the barrel, so you should always measure out where the correct position is for the block. If you aren't entirely comfortable with DIY, you can always take your parts to a certified AR-15 armorer or gunsmith to build your gun.

Buffer System and Bolt Carrier Group Harmony

The buffer system is one of those components that can help fine-tune the felt recoil and performance of the rifle. However, the buffer system must be compatible with the bolt carrier group. I used the Faxon 5.56 Gunner Lightweight Nitride-Chameleon PVD bolt carrier group, which weighs only 8.5 ounces for weight savings and looks superb (after all, aesthetics matter). Unrivaled Technologies manufactures a 2-Stage Dead Blow Competition Buffer designed for low-mass BCGs. It is recommended for rifles with adjustable gas systems to get the most performance out of it. Still, the magnetic dead blow system eliminates the bolt bounce so that you can make faster, more accurate follow-up shots. A standard weight buffer, for example, would not be compatible with the Faxon lightweight BCG. You need to pair it with a heavy buffer to compensate for the reduced mass of the BCG. Once you find a harmonious pairing, you will visibly notice a reduction in reticle movement and better rifle cycling.

The Cherry on Top – Muzzle Brakes

The final piece to the recoil reduction puzzle is a quality muzzle brake. I have a few top favorite muzzle brakes that are my go-to when building competition rifles. I look for adjustable or tunable muzzle brakes or ones designed to lower blast pressure and direct gases forward and off the bore line. I tried out the VF18-X Vent Forward Brake from X2 Dev Group for the first time and was impressed with the recoil reduction. It is designed to be installed in an X pattern and directs that gas in all directions to keep the barrel from rising or moving left or right.

For the last year or so, I have been using the Unrivaled Technologies Muzzle Brake, designed with five high-pressure points at 45-degree intervals and three low-pressure ports for fine-tuning. What I like about this brake is that you can adjust the ports to be open, partially plugged, or completely plugged to customize how the rifle moves when you shoot. I tend to push the gun to the right with my support arm, so opening the ports on the right side of the brake pushes the gun back left, essentially equaling out this movement. The other two brakes I have used in competition are the UM Tactical R.A.G.E., another tunable brake, and the SJC Titan.

All the Rest

Handguard Selection

I suggest getting an M-LOK-compatible handguard, which will provide you with the most options for mounting all your accessories. There are various profiles or shapes for handguards and different lengths to choose from, depending on your barrel and muzzle brake length. You also have options of handguards outfitted with no Picatinny rail, a full rail, or rail only at the two ends of the handguard and not in between. The Faxon Streamline Carbon Fiber M-LOK Handguard was the perfect option for this build to provide attachment points for a bipod or a sling while saving a ton of weight. Even with a 14.5-inch barrel, I wanted the 15-inch handguard to set a bipod as far forward as possible to create the most stable shooting position.

Be a Trigger Snob!

I feel wrong saying this, but a great trigger is more forgiving and allows a shooter to be a bit sloppier when firing the gun. A Mil-spec trigger, for instance, has such a long and heavy trigger pull that you can move the gun too much while trying to pull the trigger, which affects the shot downrange. A competition-specific, single-stage, 2-pound trigger requires minimal effort to pull, providing less time to move or jerk the gun. The AR Gold drop-in flat trigger has an extremely short reset and an adjustable weight starting at 3.5 pounds, and it matches beautifully with the color of the Faxon BCG. My other favorite triggers are the Hiperfire Eclipse and TriggerTech Diamond. The last tip I’ll leave you with is to change your selector switch from a 90-degree to a 45 or 60-degree throw. The HEX Selector Switch from Strike Industries is ambidextrous, allows you to change to a 60-degree throw, and gives you two large safety selectors to outfit your gun. If you’re serious about competing, you have to be a trigger snob.

Controls

The final piece of your build should be picking out controls that will be useful, easy to manipulate, and durable enough to withstand abuse. I prefer ambidextrous controls in as many places as possible because I loan my guns out to many shooters. I have met at least 30 left-handed shooters now who can’t just borrow any rifle. The T-Bone Charging Handle from Strike Industries is ambidextrous and doesn’t have too wide of handles where it can get uncomfortable to sling the gun on your back. I despise the standard small bolt catch/bolt release buttons on just about every stock rifle. I prefer oversized controls and look for an extended bolt catch I can easily manipulate in the dark, with gloves on, and am almost guaranteed not to miss. The Strike Industries Extended Bolt Catch is the answer to this, and what I appreciate the most about the Bully Arms lower receiver is instead of a roll pin, it uses a set screw to install the bolt catch. There is zero chance of marring the finish with this! The magazine release is the last component I prefer to be extended and enlarged. Once again, I despise the standard, small, hard-to-reach button installed on most stock rifles. The AR Modular Magazine Release has three sizes to choose from.

Have fun picking out each part and component. Remember that this is your gun build, so while listening to input or recommendations is okay, choose the parts that work best for you. 

Sound Off

If you've recently built a rifle, let us know! We'd love to see what our readers have done to customize their rifle to their tastes. Interested in more guides? We'd also be interested in what you want to read. Email us at gaeditor@outdoorsg.com with the subject line "Sound Off".

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