The AR-15 is the most versatile weapon on the market; it can be accessorized and reconfigured in dozens of different ways using components that are largely standardized and interchangeable. Shooting them is a lot of fun, but upgrading them is a close second – maybe not quite as satisfying as dumping a 30-round mag as fast as you can pull the trigger, but it definitely as its high points.

Building an AR-15 is not particularly difficult, but it can definitely feel intimidating to the uninitiated. For those who are new to the platform, one of the best ways to learn what can be done to an AR-15 is to start with an entry-level rifle, and slowly customize it over time as your budget permits (for a list of good entry-level rifles, check out our previous article HERE). This helps build familiarity with the rifle and confidence in one’s abilities, with little risk of breaking anything important. After changing out the handguard, stock, pistol grip, trigger, barrel, and muzzle break, building one from scratch doesn’t seem so difficult after all. For the new builder, start with the easy mods first, and work your way up from there. From easiest to most complex, the following are mods you can do to your rifle.


Rifle accessories don’t require changing the rifle itself, just bolting equipment onto the rails. The most common accessories for an AR-15 are:

  • Optics, which help you accurately engage targets at various distances.
  • Back-Up Iron Sights, which provide a point of aim if your optics fail or lose battery life.
  • Forward Grips, which better enable you to stabilize your rifle when firing.
  • Flashlights, for low-light engagements.
  • Lasers, for rapid target acquisition.
  • Rail Sling Attachments, because not all rifles have sling attachment points built in.
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Pricing of different types of accessories will vary widely, and the importance of those items are entirely subjective to the user. If you’re looking for long-range accuracy, a good magnified optic is definitely important. Conversely, someone looking for quick acquisition at close-range would probably opt for a red dot sight instead. You could also get a red dot & magnifier combo, which provides you with the best of both worlds. With so many accessories on the market, the options are limited only by your intended use and disposable income.

AT3 ALPHA Red Dot Sight with RRDM 3x Magnifier
The AT3 Tactical ALPHA red dot sight features Shake Awake for battery saving, and pairs perfectly with the RRDM 3x Magnifier for a flexible optics setup.

The best part about accessories is that they aren’t permanent. You can buy something, try it out, and if you decide it isn’t quite what you want, sell it and get something different. Experimentation is the key to finding the best AR configuration for you, so don’t be afraid to try something new or different – the worst that can happen is you decide you don’t like it, in which case you take that accessory off your rifle, sell it to someone else, and get something more in line with your preferences.


A Basic AR15 with a Magpul Furniture Kit Installed

Furniture is a broad term that refers to the stock, pistol grip, and handguard of a rifle. These are the most common components to change because they require very little time and effort on your part. Most can be installed in minutes, and require no special skills or tools – a decent set of Allen wrenches and a screwdriver with changeable bits is typically all you need to get the job done. The best part is, even if you completely mess up the install (it’s hard to do, but theoretically possible), the rifle will probably still function just fine.

One of the biggest reasons to change the furniture of your rifle is comfort. Many entry-level rifles come with a standard A2 furniture set, which is certainly functional, but not the most ergonomic solution. Some of the best upgrades are the simplest ones; a new aftermarket pistol grip, stock, or handguard can make a world of difference in how your rifle feels and shoots.

MFT Minimalist AR-15 Collapsible Stock - Commercial Spec
MFT Minimalist Stock

You’ll need to confirm whether the rifle is mil-spec or commercial-spec before you pick a stock. If you have a commercial-spec rifle, consider getting an MFT Minimalist; it’s one of the lightest stocks on the market, and one of the best options available to commercial-spec rifles. If you don’t like the look or feel of that, the Magpul MOE is another great commercial-spec option.

There’s also an aesthetic component to furniture upgrades as well – with a new stock, handguard, and pistol grip, the rifle will look completely different than when you bought it. Adding a Magpul MOE furniture set makes a basic AR look and feel like a whole new rifle. Most aftermarket furniture is not only better ergonomically, but also a lot better looking than the stuff that comes with your rifle from the factory. With furniture upgrades you’ll get immediate satisfaction without the risk of screwing up something important.

Magpul MOE M-LOK Furniture Kit - Stock, Carbine Handguard & Grip
Magpul MOE Furniture Kit in FDE with Angled Foregrip

Drop-In Parts

Most AR-15 parts are able to be changed out easily, and upgrading some of those drop-in parts can make an incredible difference in the functionality of your rifle. There are so many components that it can be difficult to know what changes will be the most impactful, but don’t worry – we have a list.

The trigger is arguably one of the best things to upgrade on an entry-level rifle. Most basic AR-15s have mil-spec triggers, which are functional but not spectacular. Often they can feel “gritty” or “creepy”, and not have a real discernable break point. If you haven’t upgraded your trigger yet, DO IT! A two-stage trigger will change your AR in ways you can’t even imagine.

AT3™ 2-Stage Lower Parts Kit with 1005 Tactical Nickel Boron Trigger - No Grip or Trigger Guard
1005 Tactical 2-Stage Nickel Boron Trigger

A two-stage trigger provides a light pull up until the breaking point, where you hit a “wall” that requires a little more pressure in order to fire. This allows you to take up the slack in the trigger and know exactly when you’re about to fire. Your initial shots will be cleaner and more accurate, and your follow-up shots will be better than they have ever been. Don’t believe me? Try it for yourself and see what all the fuss is about!

Another simple upgrade is the gas block. If you have a big, clunky railed gas block, your handguard options are limited. Free-floating handguards are one of the most popular AR-15 modifications, but they require a low-profile gas block. Fortunately, the parts are not horribly expensive and don’t take long to install. You can also get an adjustable gas block to better control how much gas is used to cycle the bolt – this can reduce “felt recoil” significantly. Paired with a two-stage trigger, and adjustable gas block will let you fine-tune your rifle’s performance for better follow-up shots.

AT3™ Low Profile Micro Steel Gas Block - 4 Sizes Available
AT3™ Low Profile Micro Steel Gas Block

Another great drop-in part upgrade is a bolt carrier group (BCG). The stock version you have is probably fine, but a black nitride BCG can be beneficial, especially to those who put a lot of rounds downrange. A black nitride BCG has a low friction coefficient, allowing your rifle to cycle more smoothly with less lubrication, and is easier to clean than a BCG with a phosphate finish.

AT3 Black Nitride BCG

Finally, one more simple replacement that can make a world of difference is an ambidextrous charging handle. For some reason, most entry-level ARs come with a charging handle with a latch that is only on the left side of the weapon. With ambidextrous charging handles, it doesn’t matter if you’re right or left-handed – either hand can manipulate the charging handle without issue. This is especially beneficial for left-handed shooters, or those who want to be able to shoot with their non-dominant hand if needed.

Armaspec Victory Charging Handle for AR15

Legally Sensitive Parts

The modularity of the AR platform has its downsides as well – the biggest one is that if you buy and install the wrong parts, you could find yourself in a whole lot of legal trouble. There are two main components that are subjects of prime legal concern – the barrel and the stock. Before we dig into this topic, let’s go over some facts.

According to federal regulations in the US, a rifle is considered a shoulder-fired weapon with a barrel length of no less than 16 inches, and an overall length of no less than 26 inches. The term “shoulder-fired” implies the use of a stock, and the barrel length includes muzzle attachments that are permanently attached to the barrel. All ARs purchased new from your local gun store will fit these criteria. Often, they have a collapsible stocks and 14.5 inch barrels, but those barrels come with a pinned and welded flash suppressor that adds at least 1.5 inches to the barrel length, and even with the stock collapsed the rifle will not be less than 31 inches in overall length.

Faxon Firearms 11.5 inch Gunner Barrel - 5.56 NATO - Mid-Length - 4150 QPQ
Faxon Firearms 11.5 Inch Gunner Barrel

Now, if you were to replace your new-from-the-factory 14.5-inch AR barrel with a 11.5-inch barrel, you would be in violation of federal law. This sort of weapon is considered a Short-Barreled Rifle (SBR), which is defined as a shoulder-fired weapon with a barrel length of less than 16 inches. SBRs are restricted by the National Firearms Act (NFA) – technically, they can be owned in the US depending on what state you live in, but you have to apply for and pay a fee for a tax stamp and go through a lengthy background check process.

SB Tactical SBA4 AR15 Pistol Brace
SBA4 Pistol Brace

A “middle ground” for this type of firearm is the AR pistol – a firearm that is NOT designed to be fired from the shoulder, and may have a barrel length under 16 inches. AR pistols are typically equipped with either a plain buffer tube or a stabilizing brace. The brace is legally not a stock, though it may look like one at a glance. It is intended to stabilize the weapon against your forearm when firing, and was initially designed to help wounded veterans accurately fire an AR one-handed. Stabilizing braces also may not have a length of pull greater than 13.5 inches – above this falls into “shoulder stock” territory in terms of comfort, according to the ATF.

SB Tactical SBA3 AR Pistol Brace
SBA3 Pistol Brace Installed

Now, if you are in possession of a complete rifle, you CANNOT legally convert it into a pistol just by swapping out the barrel and adding a stabilizing brace. Physically, is it the exact same thing as an AR pistol? Yes, but according to the ATF, if the weapon was manufactured as a complete rifle, it must remain a rifle; you can legally apply for a tax stamp to make it a short-barreled rifle, but you cannot convert it into a pistol – doing this is 100% illegal. Strangely enough, the opposite (taking an AR pistol and turning it into a rifle) is just fine with the ATF.

We just covered a lot of complicated legal technicalities in a very simplified format, but the important part to remember for those of you who want to mod your entry level AR is (a) you cannot have an overall length of less than 26 inches (from the tip of the muzzle to the end of the stock), and (b) you cannot have a barrel length of less than 16 inches. As long as you stick within those constraints, you’ll be just fine from a federal standpoint. Other laws may apply on a local or state level, so do some research on those before trying to mod your rifle (especially in California, Connecticut, Hawaii, Illinois, Maryland, Massachusetts, Minnesota, New Jersey, New York, Ohio, Washington DC, Virginia, or Washington State). We have great selection of high-quality barrels in stock if you’re looking for a replacement; you might also want to check out our article on what to look for in an AR barrel if you want to do some more research on the topic.

One Last Tip

If there’s anyone that knows the AR-15 platform, it’s the US military. As a special offer for our readers, you can get the Official US Army Manual for AR-15/M4/M16 right now – for free. Click here to snag a copy.

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6 thoughts on “The Best AR15 Upgrades

  1. Hello, I’ll first start by saying I live in New Jersey. (Saying it as I cough). So I bought a TROY m4 “other” firearms, last year. It sat for about 8 months before I even bought bullets and went to the range. I have been told many different things about my gun. First I was told my barrel is to short and I needed to have a fake suppressor pinwelded to make up the extra length. Then I was told that wasn’t true as long as my length from the end of buffer tube to the end of the threads on the barrel was at least 26 inches. As it stands now in at almost 27 inches.
    I figured you are the experts so I ask you, is my gun legal?

    1. Hello August!

      A rifle’s barrel length needs to be 16.5″ regardless of overall length. If your barrel is shorter than 16.5″ you can make up that length with a muzzle device that is pinned and welded. If your barrel is in fact too short and needs to be pinned and welded make sure the weld is visible. It doesn’t look pretty but it proves that its actually welded. If it is getting pinned and welded the gas block needs to be on the barrel!

      In the event its too short and you need it pinned and welded you should remove your barrel (and the gas block/gas tube) from your rifle and separate them until the job is done.

      If someone was to check your barrel length in the field they have been said to measure it by putting a rod down the barrel until it meets your bolt face. That would be how they get their measurement of length.

      Overall length is a factor but it by no means changes the minimum barrel length for a rifle. A rifle needs a 16″ barrel (most are 16.5 so you don’t get an official with a defective tape measure telling you that you are breaking the law) AND an overall length of at least 26 inches.

      Hopefully this was of some help and good luck!

  2. can I get a catalog 745 county rte 10 windham ny 12496 for the ar15 accessories plz

  3. As you mentioned, changing out the trigger in your weapon can greatly change the experience that you have. My husband recently got an AR-15, and he would like to upgrade the trigger. I will have to let him know that it is in fact possible to do.

    1. Dear AT3 Tactical

      I’m looking for a good Bipod to place on the bottom rail of my AR-15 Colt carbine! There are many of them out there with prices from $ 23.00 then up to
      $ 90.00 for what looks like the same item, just with a different package and name on it. Can you guide me to the right ONE TO PURCHASE! My shooting is at what we call Rockchucks and others call them Marrments. Idaho Spud
      Farmers call them crop thefts or
      Thank you for your time
      Valray Ferrin

      1. Hi Valray,

        Glad to hear from you. You may want to check this UTG Super Duty Bi-pod with QD Lever Mount, Height 6.0″- 8.5″. It has a Quick Detachable Lever Lock in Mounting Base to Fit on Any Picatinny/Weaver Rail.
        Hope this helps.

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