Best AR-15 Upgrades – What to Consider and WHY

What are the best AR-15 upgrades you can do to enhance the function and reliability of your rifle? With the outbreak of the Covid-19, AR-15s are moving faster than they have since the post-Sandy Hook panic.  With these record sales, many people have just picked up their first rifles and now are left wondering what to do next. 

The answer depends a lot on what you managed to pick up. If you were lucky enough to find a BCM, a Barrett or an H&K, most of this isn’t going to apply to you.  If, on the other hand, you grabbed something that was a bit more budget-friendly, there are a few definite upgrades that are available to you right now.

Best AR-15 Upgrades – Don’t Forget to Upgrade Yourself

Before we get into the best AR-15 upgrades and things you can do to make a gun more reliable, I want to address one thing for newer shooters.  One of the first things you should do when you have picked up your rifle is to take some quality training courses. Aside from an upgrade that is necessary to make your rifle more reliable, training and subsequent practice is the most important thing you can spend time and money on (in regards to your firearm). Once you have the gun in a place where you know you can depend on it, get some training, and then practice as often as time and budget allow. 

Get some training…

With that out of the way, reliability and function are the areas you should be focusing on with your gun in terms of upgrades.  If an upgrade isn’t adding some function or making the gun work better and more consistently, it can wait until you are a bit further down the road of owning it.  This is even more important if budget is a big concern.

Best AR-15 Upgrades – Sights and Optics

Depending on what you purchased, your rifle may or may not have come with some sort of sight or an optic setup.  Since many folks bought guns intending to protect themselves and their loved ones, that will be the main mindset we focus on.  For a defensive gun, my opinion is you go either red dot, or low power variable optic (LPVO).  Neither optic is the “correct” answer, it will largely depend on what you are comfortable with.

Or you can put both on a Badger Ordnance Condition One mount...

For red dots, the main factors to look for as a newer shooter are ease of operation (turning it on/off and adjusting brightness), battery life, and reliability (in terms of how durable it is, how well it holds zero, etc). These are the main things to consider if all conditions are ideal.  If you have astigmatism or other vision issues, that needs to be factored in accordingly.

 If the optic is operated with buttons, like some of the Sig Sauer red dots or Holosun red dots, they need to be easily accessible and respond when pushed.  If it is a dial operation, like a lot of Aimpoints, it needs to be something you can do while still holding the gun.

Battery life is also not something you should compromise on.  With many offerings in the red dot market having a 50,000-60,000 hour battery life, there is no reason you should have to turn your optic off and on each time you pick the gun up.  This is hugely important for a home defense gun, as you need to be able to wake up from sleep, grab your gun and have it be ready to use.  Anything that impedes your ability to do that, like having to turn an optic on, is costing you precious time. 

Holosun HS503R 2 MOA Micro Red Dot Sight

Prices accurate at time of writing

Finally, If your optic isn’t sturdy enough to handle hard use, while still maintain a zero, what good is it?  I’m not saying you should take a gun and repeatedly drop it so that the optic hits first, but I am saying it should be able to survive being dropped in an emergency.  Accidents can and will happen, especially in moments of high stress, so you need something that can hold up to an unintentional drop or fall.  Great examples of optics that have been abuse tested and held up are the Aimpoints, Trijicons, and Holosuns (the 503C specifically).

Lower Power Variable Optics are a different animal altogether.  The advantage here is the magnification provided by the scope.  This allows close engagement shooting, but also the ability to reach out a little further to help with ranging and threat identification.  LPVOs do need to be mounted correctly, with either rings or a uni-mount, and take a little bit more work to find the proper spacing. They still need to meet the requirements for durability and reliability.  Great examples are the Primary Arms Raptor, the Steiner PX4i, and higher-end models like the Trijicon Accupower and Kahles K16i.

Examples of LPVOs…

If you simply cannot afford a red dot or LPVO, there are iron sights.  These take a little bit more effort to shoot well with, but the main advantage is they never turn off or run out of batteries.  To meet the durability requirement, I will recommend ones made of actual metal, like the Magpul Pros, Troy battle sights, or KAC sights, but there are polymer versions available.

Best AR-15 Upgrades – Weapon Mounted Light

Any AR platform gun, be it a rifle or pistol, that is going to be used for duty or home defense should have a light on it.  The only exception to this would be if you are some sort of overwatch sniper, and if that’s the case why are you listening to me instead of your team lead?  Weapon mounted lights in a home defense scenario are invaluable for several reasons. 


First, a light will allow you to identify a target.  Here is the scenario: you are dead asleep, hear the noise of a door being opened loudly and immediately grab your gun.  Would you rather shine your weapon light into the entryway of your house and see if it is an actual threat, or blindly fire at a shadowy figure and risk harming a loved one.

“But Todd, won’t I give away my position?”

Yes. Is it still very much worth it to run a light? Absolutely, without a doubt, yes, you should run a light.  Beyond getting a positive ID on the target, you’ll also have the advantage of blinding your adversary. This is a two-fold benefit.  First, they won’t be able to see momentarily, but second, you have the home-field advantage.  While the person who broke into your house is blinded and trying to figure out how to either close the distance or get a good shot off, you know the layout of the house, you know where furniture generally is, and you should very much be using that to your advantage.

The key here is finding quality that runs when you need it to, and that is rugged enough to be smacked against things and not fail.  Lights that are worth doing homework on are the Surefire Scout line, the Arisaka lights, and the Modlites.

Arisaka Defense 600 Series Momentary 350 Lumen Weapon Light

Prices accurate at time of writing

Best AR-15 Upgrades – Slings

Slings are an often overlooked area in terms of home defense guns.  To an extent, I understand why they aren’t shown the same priorities as a quality optic or a light, but they are essential to any duty or defense gun. 

The primary function of a sling is going to be keeping the gun on your body.  This may seem obvious, but there are a couple of instances where this is of prime importance.  First, if you have to pick up a loved one, you can now do so without setting your firearm down in a potentially compromised area.  Second, if things do end up in a bad way, the sling retains the gun for you so your attacker cannot simply pull it out of your hands. 

Beyond that, a sling can aid in accurate shooting.  One issue that newer shooters have is keeping the long gun tight into their body (ideally the shoulder, but that is a different topic).  The support hand that holds onto the rail or handguard should be pulling the gun into you and then guiding where the point of aim is.  For people having trouble keeping the gun tight, wrapping that support hand in a sling and using it to create a method of pulling back towards you can help with shot placement.

Details of a Vickers sling…

For a sling, you want to look for something comfortable and easily adjustable.  I am a fan of the Ferro Slingster, the Blue Force Gear Larry Vickers sling, the Lunar Concepts sling, and the Magpul MS4.  All of these slings allow for a quick-adjust, many offer a single point conversion, and are quality products that won’t fail when needed.

Best AR-15 Upgrades – Improving Reliability

This is probably the toughest section to gauge whether or not you need to spend time on it.  Any of the upgrades in this section will be dependent entirely on what you managed to purchase.  Areas that are worth looking at will be the bolt carrier group, fire control group (especially springs), barrels, and in some cases the handguard or rail.

Bolt carriers are not all created equal.  Things like staking on the gas key, fasteners used to attach the gas key, tooling marks and burrs that inhibit bolt movement, and more are all indications your bolt carrier may need to be replaced.

Fire control groups suffer from similar glaring issues that require replacement.  Many less expensive lower parts kits use underpowered springs for the hammer and trigger. This, in turn, can cause light primer strikes when your gun is being fired.  This is a problem that is shared by many lower-end cassette-style triggers. If this is a common occurrence, replacing the springs, or the entire fire-control group is basically necessary for the gun to function.

Handguards and rails will vary depending on what came with your gun and if you have a fixed front sight.  I am not a fan of the plastic A2 style round plastic handguards.  That is due largely in part due to lack of ease with attaching necessary components.  I’m also not a fan of rails that are so small in diameter that they lack the durability to survive a drop.  Find what fits your budget best, fits your hand well and allows you to attach the parts you need with ease and reliability.

Best AR-15 Upgrades – Conclusion

This is just a small list of possible upgrades available to an AR owner.  Prioritize what you need for your situation and application.  The whole point of your purchase is peace of mind and safety when needed, so don’t neuter yourself by running with a less than ideal setup.  Once you have your gun in a place and feel it’s good to go, practice with it and get to the point that it is second nature for you.


Todd Gimian is a gunsmith based out of Las Vegas, Nevada. After receiving his degree from Sonoran Desert Institute, Todd has spent his time building and maintaining a variety of machine guns and product testing for various companies. His main focus is expanding his knowledge on the AR-15 platform and helping bring better quality products to the market for end-users to enjoy.  

Did you find this article useful?

Let the author know with a 5 star rating!

Average rating 4.7 / 5. Vote count: 24

No votes so far! Your rating will help us continue to provide valuable and interesting content.

Since you found this post useful...

Follow us on social for first dibs on brand new content!

We are sorry that this post was not useful for you!

Let us improve this post!

Tell us how we can improve this post?

Notify of

1 Comment
Most Voted
Newest Oldest
Inline Feedbacks
View all comments
1 year ago

I appreciate you helping me learn more about AR-15 upgrades. The article was very interesting and I liked how you gave recommendations and examples for each part that could be upgraded. Do-it-yourself upgrades are never easy and it is important to do what is comfortable for you and what you can afford. 

If you want to be among the first to know when we release new content, your best bet is to sign up via email:

We’ll keep the emails to a minimum and we will never sell or give your information to a third party.

Would love your thoughts, please comment.x