Tactical Weapons Firearms

Customizing an AR-15 from the inside out

Customizing and building your AR-15 is a very intimate process. You’re fine-tuning it to meet your specific needs. Let us help you out.
Brady Kirkpatrick Avatar
customizing an ar-15
Photo credit: dlewis33 (Getty Images)

Customizing and building your AR-15 is a very intimate process. You’re fine-tuning it to meet your specific needs. Every part is put together in pursuit of your desired outcome.  You probably know what you’re using the rifle for at this point. 

You’re making it do what you need it to do. And once the process is done, it’s a 1:1 rifle that nobody else owns. It’s yours. But what parts should you change to make the most difference in your rifle? 

Here is a guide to customizing an AR-15 from the inside out

It’s what’s inside that matters

Your firearm’s inner workings make it reliable, accurate, and overall a better fighting rifle. 

These parts matter the most. Because if you don’t have reliability and accuracy, then you might as well hang your hat. 

Buffer and Buffer Spring

For a lighter recoil, you can start by replacing the buffer and buffer spring. 

Consider the weight of the buffer that your rifle that it came with. They come in a few different weights and can sometimes come with a lighter buffer than you call for. 

The spring could also be replaced for one with heavier tensions. Spring makers like Springco have a chart on the bottom to guide you, so you don’t buy one that’s too heavy. 

Bolt Carrier Group

This is the heart of your rifle. Your bolt carrier group is where the magic begins, and it takes a lot of abuse. So you should be sure it can handle the job at hand for a long time. 

It should be properly staked, HCI and MP tested, shot peened, and chrome lined in the inside. 

And there are many options to choose from. From my experience, Colt is the most consistent with their BCGs. BCM and Sons of Liberty do a great job, too. 

Charging Handle

Just make sure you buy one that’s durable. I’ve seen charging handles snap in half from simple use, so try and make sure you get one that’ll hold up to the abuse you plan on putting it through. 

I would suggest one that’s ambidextrous if you’re going from shoulder 

ar-15 for sale
Photo by Jabin Botsford/The Washington Post via Getty Images.

You can put lipstick on a pig…


Slings help you keep the rifle close to your body so it doesn’t slip away from you or hit the ground if you need to switch to the pistol. 

They can also help you stabilize the shot if you wrap your support arm through the sling itself and back to the grip, which pulls the rifle into your shoulder and stabilizes the shot. 

They also come in different configurations from one, two, or three points. Each sling has its own benefits, from maneuverability to keeping the rifle tight to the body.


Adding a foregrip to the bottom of the rifle will help you keep the rifle on target and give you more maneuverability.

Foregrips also make it easier to pull the rifle into your shoulder with isometric tension. Push your shoulder into the rifle and pull the rifle into your shoulder. 

There are many options out there, including those that can be used as a bipod. It took me two tries to find the one for me. 


Instead of lining up iron sights, now you can put a reticle on something and shoot. It’s quicker, easier, and smoother. And it helps keep things precise. 

If you plan on shooting further, you can benefit from an LPVO. The beautiful part is if you want to use your rifle for both short-to-medium and long-distance range, you can add an offset red dot. 

Your more durable optics come at a price. And anything that has “proven itself on the battlefield” will cost significantly more than something fresh off the boardroom table. 

Depending on what you’re using that rifle for, whether it be the boog or for range time, buy what you need. 

Lights and lasers

Put a light on it. 

Positive identification can be the difference between taking out a bad guy and a lifetime of regret, so make sure you can see who’s on the other side. 

Lasers are an extra tool for aiming. It can also help you get rounds on target quicker in close quarters than getting a reticle over the target. But they are visible, so that could give you away.  


Buttstocks aren’t the most important, but they do help a bit. 

Some are for precision, some are for CQB, and some are for in-between. While you can run in-between stocks for both of the purposes I mentioned, finding the right one can help you with accuracy and stability. 

Building a rifle is like getting a suit tailored; it’s all about you. So figure out what you want from your rifle and start building. Just don’t fall for the mil-spec hype. 

It may take some trial and error, but that makes the outcome better. There are few things better than finding a part that makes it all come together. 

Have fun and happy shooting.