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7 Things to Look For in AR 15 Handguard Types & Free Floats

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.

 

US Army Service Manual AR 15 Ebook

 

Best Free Float Tubes

Hogue AR 15 Handguard 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.

33 thoughts on “7 Things to Look For in AR 15 Handguard Types & Free Floats

  1. Thank you so much for the article. I needed the info. Nice job.
    It seems that I saw somewhere that there is a split free float rail to where you do not have to take off the front sight and it attaches to your barrel nut and it won’t twist, either. I will look at your sight further to see what you have. Thanks again.

  2. Will the AT3 quad rail fit on an Adams Arms Upper?

  3. thanks for the info ,im purchasing an AT3 7” free float quad rail for a s&w m&p15 5.56 cal. will my front org. sight have to be replaced or will this fit ok?

    1. It should that exactly what I put on mine!

  4. Hi Paul – your original front sight will work fine with this rail!

    Bill – yes our rails work with Adams Arms uppers!

    Thanks, Zac

  5. What size quad rail will fit on a olympic arms k16 bull barrel the barrel is 16 inches

  6. I have purchased a Sig Sauer AR-15 m400 .223 16″ barrel with Direct Gas Impingement, what length of free float Tactical Quad Rail can I fit ? Thanks

  7. Great Info on the Forearm. Love the site so far. Will explore more.

  8. I’d like to replace my stock mid-length handguards with a drop in rail system. The current handguards measure 8-5/8″. Is a 9″ system compatable with those 8-5/8″ handguards?

    Thanks.

  9. Can you change a drop in quad rail hand guard for a free float hand guard? Can the a free float work with the spring loaded delta ring the same as a drop in.

  10. M16 Colt is a wonderful gun
    I need a full catalog for it free
    and amodel please

  11. My question is…if i were to mount iron sights or an optic onto a free floating forearm and the rifle got bumped or dropped would the sights or optics be more likely to be out of alighnment on a free float compared to a fixed forearm?

  12. Orrin, from my experience, no. With a free-float forearm, the rail is ridgedly attatched to the receiver. As long as you have a quality rail, it won’t move around on impacts unless they are strong enough to damage the rails. I have a nine year old Daniel Defense Omega rail (free floating) mounted on my 20″ rifle and the sights (front iron mounted on rail, rear mounted on receiver) have never come off zero due to an impact. Granted, I’m careful with my rifles, but it’s still fallen short distances on occasion. If you are going to mount an optic on an AR, free-float is the way to go. Drop in handguards can shift due to pressure on a given point, throwing off optics. Now, my experience with these things is limited (one drop-in tube, one drop-in quad rail, and one free float quad rail) so I can only speak from what I’ve seen. Most people recommend free floating forearms for optics of any kind.

  13. Great article. Very informative. My only question is, why the huge cost difference in free float rails? Some are as low as $50 others as high as $400. I am not sure iif the cost is worth it.

  14. mitch, whether the more expensive rails are worth it is almost completely dependent on your use of the rifle. The quality of the materials, QC, strength, weight, and (less importantly) looks factor into the price of a free-float rail, much like with anything else. Though there are exceptions and many people are happy with fifty-dollar rails, they likely won’t be of the same quality as the more expensive counterparts. They are more likely to break, probably aren’t as concerned with weight, probably didn’t see extensive QC to ensure they will fit or function properly, and probably are simplistic in design. As I told Orrin, I have a Daniel Defense Omega rail that, after almost ten years, is still holding strong. It is extremely light weight, but it is as sturdy as they come. Obviously, I am a proponent of the higher end rails, but if you just want something to toss a cheap light on, the cheaper rails will do just fine. Just don’t expect them to hold up forever or take too many hits and be prepared to deal with poor QC. If you are mounting a lot of equipment, are hard on your rifles, or are planning on adding an expensive optic to your rifle, dish out the extra cash now and save on replacements down the road. If you are building a budget rifle and want a rail for light use, then buying a 400-dollar rail will be pointless (unless you just like the looks). I went with the Daniel Defense because I wanted a light-ish weight rifle and planned on putting a nicer scope on my rifle (which I am FINALLY about to do). My advice: buy the nicest rails you can afford. If you have 150 to spend on rails, spend 150. If you only have 50 bucks, either make due with what you can get or save a bit more. I’ll personally cheap out on some stuff, but optics, triggers, barrels, and forearms are some of the only things that I’ve learned to be picky about.

  15. Great and impostant article, however, there are a couple things I’d like to bring up. First: “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 very slightly warp the barrel.” That aluminum/polymer handguard is going warp long before that chrome moly steel barrel is going to warp and to be honest, I’ve never heard of a bipod attached to a barrel bending it. I have heard rumors. Second: The effectiveness of free float handguards on the AR platform depend on a great deal of things. Was the barrel extension bent or twisted when the barrel was installed? Is the barrel extension straight? Is the barrel nut perfectly machined? Was the rail perfectly machined? Are the screws holding that rail on permanently secured? The point is the AR platform was never intended to be a tack driver, it is a combat rifle. I’ve seen several free float handguards that either weren’t attached properly or weren’t made properly. I’ve seen them come loose. In any of these instances they will not be “true.” Most free float handguards are secured to a special barrel nut by six screws, which itself is secured to the barrel and the barrel extension. Some have an end cap that is secured by more screws, which may or may not be touching the barrel. So yes, technically it is not attached to the barrel but it is attached to something that is attached to the barrel. Regardless of how many screws, the whole setup depends on no movement of the rail, that the rail is straight (if you have an iron sight) and those screws holding up. I personally have never seen a drop-in that wasn’t tight and locked up, being clamped in place with the delta ring, a VERY strong spring and the end cap. I’m sure there are exceptions if you go really cheap, as with anything.

    I know it appears I’m doing a “hatchet” job on this article – I am not and it is well written, however, there are potential issues with free float handguards that people should know. I will add that a nice drop-in will likely be in the $60 – $120 price range, a nice free float setup (handguard, barrel nut, shims, sleeve, screws) will cost $180 and up (potentially $300+). A “classic” drop-in can be had for $20 – $30. Installation of a drop-in requires no tools and is hard to screw up, a free float probably shouldn’t be installed by a novice and they require special tools (vise, torque wrench, upper receiver clamp, etc.) and knowledge. Additionally, many people attach a front sight to the end of a free float – again, if it’s not straight or secure, it will be useless. I’ve never seen anyone attach optics to a drop-in handguard, only “tools” (light, sling attachment, laser, etc.). All said, I have four AR’s with both types of handguards. I like both. If accuracy was my prime concern I would go with free float as the author states. As for who I am: I build my own rifles (AR’s), I’ve served in the Army/Army Reserve for 38 years, I’m a retired state trooper and a POST certified firearms instructor/range master. I am very familiar with the AR platform and again, I wish to stress that it was designed as a combat rifle – it was never intended to be a sniper rifle or a tack driver, it’s design for this purpose is flawed. If you want superb accuracy go with a glass or polymer bedded bolt action rifle. I hope I’ve made it clear this is a great and informative article – I’m in agreement with the author on many points – I simply wanted to point out some additional issues to consider regarding handguards.

  16. Very informative. glad to know about difference between drop in and free float fore grips.

  17. Thank You AT3Tactical for this extremely helpful and highly informative piece in the various AR15 rails. I couldn’t have stumbled across this article at a more better time than today. I’m currently in the market for a custom hand guard rail and after talking with many friends and going to my local firearms store, I was amazed at how many different kinds of rails their were and the pros/cons of each one. Of course, everyone I talked to all had their own opinion, but the general consensus was that ultimately, it boils down to personal preference and what’s the most comfortable for myself. Fortunately for me, I came across this article and not only did it provide me with enough information, it also provided me with enough to actually make a determination on what specific kind and style that I wanted. So this weekend I’ll be out shopping for a new rail and I’ll save a ton of time because I already know which one I want to purchase. Thanks again AT3 Tactical for posting this informative and in my opinion “A must read” article if you’re in the market for a new hand guard rail for an AR15.

  18. I have a Ar-15 with a 20 inch barrel. I’m looking for a different free floating railing system, something that would cover most over the barrel. Any suggestions? I’m a rookie here. thank you in advanced for the help.

  19. Very helpful, thanks!

  20. Thank you for this article! I have a Firefield carbine length drop in quad rail handguard on my spanky new M&P 15 5.56 and it does get quite warm. Is there anything that can be done for this? I want to get the Magpul Magpul AFG2 Angled Forend Grip, but I don’t want it to melt with use… Any advice?

  21. James, assuming your handguard is heating up due to your barrel temperature rising, there are a few things you can do to remedy the situation. One option is to get a heavier contour barrel. Thin barrels tend to heat up quicker since the heat from the expanding gasses only has to heat a small abount of metal to reach the outside. The trade-off of a heavy barrel is that it will take more time to cool completely, for the opposite reason.

    Another option is to buy a freefloat handguard. Freefloat handguards minimize contact with the barrel, so it shouldn’t heat up from firing much, if at all.

    But before dropping big bucks on new parts, consider evaluating how you are firing. If you are shooting in such a manner that your barrel is heating your handguard to the point that you’re worried about something melting, that tells me that you are firing quite quickly and not giving your rifle a break. If you are doing some sort of speed competition, that’s fine, but be aware of the problems this will bring up.

    For one thing, as your barrel heats up, your accuracy will visibly decrease. Hot barrels are more “flexible” than cold ones. This causes what is known as “walking” of the barrel, where your barrel may shift a few degrees from shot to shot, causing a matching point-of-impact shift.

    In addition, heating up your barrel, then continuing to fire without break is hard on your chamber and the beginning of your rifling. This practice will reduce barrel life by quite a bit.

    Ideally, if you are shooting for accuracy or even just want to make a plinker last as long as you can make it, you would shoot slowly and methodically. Don’t get me wrong, I’ve been guilty of doing a couple of mag dumps, but most of the time I will fire off five to ten rounds with a few seconds between each shot, then wait a couple of minutes to relax my barrel. Once I feel the barrel becoming noticeably hot, I let the rifle sit for ten to fifteen minutes (less if it’s cold out) or until it is back to the atmospheric temperature. Even shooting slowly for too long without a break can heat up a barrel too much.

    Honestly, I’ve used Magpul products and they are very well-made. I wouldn’t worry too much about an AFG melting, since it would require a pretty high temperature. My biggest worry would be the waste of ammo and how hard on your rifle that much heat would be. A hot barrel is a bigger problem than a hot handguard. Hot handguards should just warn you of how hard you pushed your barrel.

  22. Great piece of information! Thank you very much.

  23. Thank you for forearm article. I’ve been thinking of this upgrade but was confused as to options. One question though. How can i tell if my gas block is small enough for float quad rail and how do i install?

  24. Hello All.
    Long story short I have a DPMS 20″ bull barrel with rifle length gas system, & a .936″ gas block seat.
    Here is the tricky part. Down the barrel, towards the action, from the gas port the barrel expands to 1 1/8″ in OD.
    When it was on the original rifle it had a free float tube, with no ability to mount anything.

    ***Actual Question***
    Does anyone know of an at least 15″ free float forend that doesn’t weigh a ton and has a barrel nut that can accommodate such a wide barrel? or Does anyone know of an AR 10 forend that will fit on an AR15 receiver?

    Thanks!

  25. I’m just now getting back into rifles after only keeping pistols for home defense. I did spend quite a lot of time around weapons in my 6 yr. military career. Large machine guns down to small arms. It’s been almost 22 yrs. since I’ve handled a rifle like this and much less a M2.50 cal. or Mark 19. I’ve recently built an AR-15 5.56 variant that I’d like to start upgrading. It’s built with a floating 16″ barrel. “Heavy” 15″ Key mod hand guards I’ll upgrade 1st. (Any advice on light, strong, affordable and less busy hand guards than what I’ve found lately). I like the rails and only in the spots I need iron sights. The full rail along the top is a bit much. The rest is much like my G.I. A-2 but with rails and no carry handle. I also wanted to say thanks. Thank s for this helpful website. It’s been instrumental while I built my AR-15.

  26. If you’re looking for a FF handguard and need help deciding which one to go with, I suggest you check out the AR15 Parts Weights Database. Google it. Over 1450 rail systems are currently included, which attachment system, weight, ID, length, and material all included as specs. It’s the best parts selecting tool on the internet…and not just for rails!

  27. save your money for a handguard and switch your rifle to a piston drive like a m14 I know you don’t have to shoot rapid fire to get it to hot handle without a glove, every shot gets it hotter ammo, your bolt and hands get to cookingThe gas system keeps pouring hot gas into it !

  28. Handgaurds and foregrips aint the same thing !

  29. I want a free float handguard for my s&w mp15 sport 2 223 556. Any suggestions. I want to stay in between 50 to 150 on the price. I like quad rails but open to other options. I’m new to accessories so want a good bit for myself.

    1. Hi Darrius,

      Thanks for your interest. Our Spear handguard would fit well on your M&P15 Sport II. It is simple to install, lightweight, and easy on the wallet.

      Hope this helps.
      Alvin

  30. Free float hand guards have two different thread diameters

  31. One thing I didn’t see above is that, not all free-float handguards are compatible with “billet” uppers. I was building a 9mm AR and, I had chosen a Matrix Arms side-charging upper. I wasn’t paying attention when I chose to use a Midwest Industries MLOK handguard and, due to the mechanism that locks the rail on the handguard in alignment with the receiver’s rail, it wouldn’t fit. The bottom/front of the receiver was too wide to accept the locking tabs. I really wanted to go with that combination so, I took the receiver and the handguard to a gunsmith. I had him mill small reliefs in the bottom/front of the receiver to accommodate the locking tabs of the handguard. Afterwards, it fit perfectly but, it cost me an additional $80 for that oversight. I did go back and look at the website where I ordered the handguard and, it clearly stated “not compatible with billet uppers”. I should have paid closer attention. Lesson learned.

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