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By Brad Steenrod

AR 15 Handguard: Free floating or drop-in? Aluminum or Polymer? Quad rail, Keymod, M-LOK, or no rail?

Choosing a handguard for your AR-15 can be confusing, with all of the options that are available. Even the names can be confusing (handguard, forend, forearm, foregrip – they’re all the same).

But picking the right handguard is one of the most important decisions to make when building or accessorizing your AR-15. The AR 15 handguard can define the functionality and appearance of your rifle, and allow for further accessorization.

AT3 Tactical SPEAR M-LOK Free Float Handguard - Available in 12" and 15" Lengths

So to help make things a little more clear, we’ve identified 7 main characteristics that you should look at when choosing a handguard.

So before reading any further, try to answer the questions below:

Look What kind of look are you going for? Classic? Military? Tactical?
Mounting options Do you want to mount accessories? What kind and how many?
Weight How much weight are you willing to sacrifice for function?
Ease of installation Are you OK with modifying your AR?
Accuracy Free float handguards can tighten up your groups – do you care?
Price What are you willing to spend?
Heat resistance Will you be shooting enough where heat will be an issue?


Keep the answers to these questions in mind as we look through the different types of handguards.

To start out – there are 2 main categories of handguards – drop-in and free-floating.

Main Category 1 – Drop in handguards

“Drop in” handguards are the classic, two-piece handguards the M4 was originally designed to use. They are called “drop in” because to install/remove these handguards, you really just need to pull back the spring-loaded “delta ring” and drop in some new ones! So the big advantages of the drop-in family of handguards:

  • Easy to install (just “drop” them in!)
  • No modifications to weapon (the stock AR 15 is made for these handguards)
  • Usually the least expensive (not much to it!)

Within this drop-in category, there are really 2 main types – Polymer drop-in handguards, and Railed drop-in handguards.

Best Polymer Drop-in Handguards

Magpul MOE Handguard

The classic M4 or AR 15 handguard is a 2-piece polymer handguard that has a metal heat-shield on the inside. They tend to resist heat well, even after lots of shooting. The polymer construction makes them very lightweight, and they are available in several lengths, and the proper handguard depends on the length of your gas system.

Magpul (and some others) also make upgraded polymer handguards, that can add mounting options, and enhance the look of your rifle.

Look Classic handguards are Plain-Jane, but some options like the Magpul handguards can dress it up a bit
Mounting options Classic handguards have no mounting options, but Magpul handguards allow for mounting M-lok attachments
Weight Very light and easy to grip
Ease of installation Very easy to install
Accuracy No accuracy boost
Price Cheap and readily available, usually less than $40
Heat resistance Good heat resistance

Best Railed Drop-in Handguards

Midwest Industries Railed Drop-In Handguard

There are also several varieties of drop-in “railed” handguards (also know as drop-in rails). Most types are made of aluminum.

The most common type is the quad-rail, which gets its name from the 4 rails that run the length of the handguard.

These rails are typically designed in the MIL-STD 1913 (picatinny) specification, but Keymod and M-LOK mounting rails are increasingly available.

These AR handguards allow the mounting of all different types of accessories. You can mount bipods, foregrips, and possibly lights or lasers on these rails. But it is not recommended to mount optics on a drop-in rail because drop-in rails have some “wiggle”.

Look Gives the rifle a bit of a “tactical” look
Mounting options Allows mounting of bipods, grips, lights, or lasers – but cannot mount optics
Weight Usually a little heavier than the classic polymer handguards
Ease of installation Very easy to install
Accuracy No accuracy boost
Price Usually reasonably priced, often less than $50. But some brands can be $150-200 plus.
Heat resistance Aluminum drop-in rails can get hot after prolonged shooting, polymer is usually OK

Main Category 2 – Free Floating Handguards

Now things are getting fun! In addition to providing better accuracy, free floating handguards can offer great customization options for your AR 15.

The accuracy of the free floating hanguard comes from the fact that the handguard doesn’t touch the barrel – it is mounted directly to the upper receiver. This allows the barrel to “float” and gives better harmonics, resulting in slightly better accuracy.

The accuracy difference is especially evident when using grips or bipods on the handguard. When you rest a rifle on a bipod that is attached to the barrel (or a drop-in handguard) the bipod will create force that can slightly warp the barrel. This small amount of warping can provide fairly significant accuracy issues down the range. But with a free float handguard, you can put all kinds of force on the hanguard and it won’t affect the barrel whatsoever.

Another advantage of free floating handguards is that you can make them longer than the length of the gas system, by using a low profile gas block. For instance on a typical AR 15 carbine, the drop-in handguard is about 7” long. But with a free float + low profile gas block, you can use rails as long as 16”! This opens up a lot of accessorization and customization option.

There are 2 main categories of free float handguards – free floating railed handguards (we call them “free float rails”), and the non-railed handguards (we call them “free float tubes”)

Best Railed Free Float Handguards

AT3 Tactical SPEAR M-LOK Free Float Handguard, seen here in 12 Inch length

Free float quad rails are the most popular type of free floating handguard. They are available in many different lengths, colors, and configurations. When used with a low profile gas block, the handguard can be as long as the user wants.

The classic railed handguard is the “quad rail” – named for its 4 picatinny rails. The problem is – they tend to be somewhat heavy, and require significant machine work (which can lead to higher costs).

AT3 Pro Series Quad Rail

Over the last few years, Keymod and M-Lok handguards have become very popular as an alternative to the classic picatinny rail. These use machined cutouts instead of “ridge and groove” for attaching accessories. The result is a lighter handguard, that is simpler to machine.

Look Tons of options available. Great for the decked-out “tactical” builds
Mounting options Allows mounting of bipods, grips, lights, or lasers and optics. By far the most accessory-friendly handguard. Some designs use Keymod or M-Lok attachment instead of picatinny rails, which can reduce weight and cost of the handguard
Weight Can vary widely between brands and sizes, but quad rails are typically a little heavier than the other handguard types. Keymod and M-lok designs can be quite lightweight
Ease of installation More difficult to install than a drop in handguard – requires partial disassembly of the rifle (about 30-45 minutes of work). Also requires special tools like a vise block and armorer’s wrench.
Accuracy .5 – .75 MOA improvement over drop-in handguards
Price The most expensive of the handguard types, with some handguards costing $300+. But some brands offer rails starting in the $50-100 range.
Heat resistance Despite aluminum construction, most quad rail handguards are vented well enough that heat is not an issue.

Best Free Float Tubes

Hogue Free Float Tube

The free float tubes are a common sight on match-grade rifles that value accuracy above all else. They provide the accuracy benefits of free floating handguards but are pretty much no-frills in design. A common manufacturer of these type of handguards is Hogue.

Look Fairly plain, but available in many different colors and lengths
Mounting options None
Weight Generally lighter than the free float railed handguards, but still a little heavier than classic handguards
Ease of installation More difficult to install than drop in – requires partial disassembly of the rifle (about 30-45 minutes of work). Also requires special tools like a vise block and armorer’s wrench.
Accuracy .5 – .75 MOA improvement over drop-in handguards
Price Reasonably priced, often less than $50.
Heat resistance Aluminum construction can cause heat issues – vents in the handguards will help

We hope this article was helpful in explaining the options in choosing an AR 15 handguard. We generally recommend researching the free float handguards as a first option. If you can’t stomach the cost or the install, there are many other options available.

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.


This article was originally published in AT3 Tactical AR Academy and is reprinted here with permission.  

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  1. >> This article was originally published in AT3 Tactical AR Academy and is reprinted here with permission.

    Ah. Figures as to why the geissele rails aren’t there.

  2. This article is rife with inaccuracies. It also doesn’t even mention the trend towards “monolithic” handguard designs.

    These are not the same:

    Handguard = Part of an AR covering the barrel
    Forend = Front of the gun towards the muzzle
    Forearm = Part of *your* body
    Foregrip= An attachment you can put *on* the forend to grip the weapon at the forend.

    Not even complicated stuff here.

    • Hey Thanks Kroglikepie,
      I am just reading/seeing this now, 9/18/18 in the am., and wanted to Thank You: for Saving Me the time (^_-) LOL
      But Still, IMHO: this article will help alot noobs,… other then some of the definitions, of which YOU broke it down nicely, Thanks again. (^_^)
      Peace Mav

  3. It is my sincerely held opinion that If your rifle is not free-floated, then you’ve willingly neutered your rifle’s capabilities.

    • Only a minority of AR owners shoot long range or participate in competitions. Most people have it for defensive purposes, the fun factor, the shtf/teotwaki/zombie apocalypse factor, and the “it is going to be banned nationwide” factor. Most owners shoot paper at the range 50yds and under, and you will probably not see the difference between a Magpul drop in or Midwest Industry, and a 5x more expensive free floated handguard. I’d rather put more $ in some other parts and features, such as the barrel, because AR15 builds with a top notch free float and a so so barrel make me shake my head.

    • Free floating the barrel really doesn’t help the accuracy much at all. What it does is stop bipods and tight slings from changing the shot group’s location on the target, not its size. Pressure on the barrel will change the rifle’s zero. So it’s real easy to mistake that change in zero for a loss of accuracy, but that’s incorrect.
      One can prove this by simply shooting a group(with a non free floated barrel, OFC) off sandbags, and then another off a bipod, and another with a good, tight sling. You will see that while the groups will be apx. the same size, they will be in different locations on the target. If the barrel is free floated, though, they won’t. Anything touching the barrel will change the barrel harmonics as the bullet travels up the tube, changing the point of impact.
      That part of the article is incorrect, or at least oversimplified.

  4. This would’ve been handy back when I started looking to buy an AR. I had to figure out the handguard stuff by looking at a lot of different products and reading between the lines. Not that it was a bad thing; I learned what I needed to know and more besides. It just wasn’t very efficient.

  5. Look: Is there any other kind of look that is not considered tactical? Isn’t the entire purpose behind the AR to be tactical? I think the term tactical is a bit overused now days. Even a hunting AR looks tactical. Tactical.

  6. Another type wold be the Aero Precision M4E1 style of upper receiver (if you are rolling your own).
    The handguard attaches to the upper receiver, making for a truly free floating handguard.

    • With the rail mount forged into the upper itself (on the ‘Enhanced’ uppers) that rail is not going anywhere.

      I use them almost exclusively now, unless I’m building something ultra-light.

      • Same here. AP’s receivers are top notch. The lack of having to time the barrel nut for the upper is worth the slight weight penalty alone.

  7. pull back the spring-loaded “delta ring”

    Easier said than done most of the time.
    That’s why I tossed all those in favor of free float quad rails or KeyMod.

  8. My most used AR15 and my AR308 has a barrel nut/handguard set up that dose not require me to have to time the barrel nut. The gas tube slides over the barrel nut. The majority of the shooting I do doesn’t see much of a benefit from a free floated set up. [read hunting and general recreational shooting inside 300 yards] The catch is I HATE TIMING BARREL NUTS so all my long guns have this set up.

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