The Best Handguard and Barrel Length Combinations | STNGR USA

The Best Handguard and Barrel Length Combinations | STNGR USA

Posted by STNGR USA on Mar 15th 2023

Last Updated: March 15, 2023

Handguards are an important piece of the modern sporting rifle. They allow us to mount equipment, hold onto our rifle without scorching our hands and they can look pretty damn cool as well.

One often over looked thing a handguard can add or subtract from an AR-15 is accuracy. Legacy drop-in handguards can typically get the job done as far as protecting your hands and allowing you to mount stuff to your rail.

However, is has been found that these drop in handguards can affect the overall accuracy of your rifle through minutely interfering with your barrel’s harmonics.

Be it from the bipod mounted to the rail, resting the rail or barrel against something while firing, or even an overly tight sling these forces can and will affect where the bullet goes.

Free float handguards were created to fix this issue of barrel warping that we see with the traditional AR-15 drop-in handguards.

Table Of Contents

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Advantages of a Free Float Handguard

  • They ever so slightly shift the center of gravity rearwards. By nature of the handguards mounting method, some weight is shifted towards the rifle’s natural center of gravity.


  • They push the rail over the gas block, protecting it from abuse. Especially if you’re rough on your rifle like me.


  • Longer sight radius for Iron Sights in comparison to a drop in rail for a similarly length barrel. This is done because we can push the rail way out past the gas block and closer to the end of the barrel. Longer sight radius allows for more accurate shots at distance


  • Better Recoil control. Now don’t misunderstand me, this is mostly dependent on your shooting style and skill level. In general though, if your rail is longer, on whatever barrel length you choose to use, you can have your support side hand further out. Using either an Angled Foregrip (AFG), forward grip, or just the trusty C-clamp style hand positioning. The further you can get your hand out there on the rifle, the better you’ll control recoil leading to quicker follow up shots.


  • Better Accuracy. Some estimates give the rifle with a Free Float Handguard somewhere between .5 to .75 MOA improvement over drop in rails. And at longer engagement distances this can mean the difference between a hit, and hitting the dirt near the target. This is achieved by letting the barrel float freely within the handguard, contacting nothing along its length. Leaving the barrel’s harmonics unaffected by forces placed on the handguard.

How To Choose a Free-Float Handguard

With today’s plethora of aftermarket support for the AR-15, there’s a lot to think about when building your rifle. Considering the intended task of your rifle is key when building it. After you’ve settled on your barrel length, you’re going to want to pick a handguard that matches the job the rifle holds.

In general keeping the rail about an inch from your muzzle device will give you plenty of room to work with, without the worry of destroying your handguard.

Be careful to select the right handguard and muzzle brake/flash suppressor combination. Especialy if you want to have the handguard extend past the barrel.

Otherwise your handguard could peel like a banana...

AR-15 Handguard peeled by muzzle device

Tactical Banana Split. Picture credit Solar Tactical

If you're unsure, we also have an interactive quiz that can help make your process of finding the right handguard! Just input some information about your build and we'll recomend the right length for what you need.

Ok, with that out of the way, let’s look at which handguard lengths are best for some of the most common barrel lengths.

The Best Handguard Length and Barrel Length Combinations

20” Barrel: The Original

HWK 15

HWK 15" M-Lok handguard on a 20" Barrel

  • 15” Handguard: If you’re running a 20” barrel as Eugene Stoner originally designed the AR-15 and looking for a free floating hand guard I’d stick with a 15”. While you can get longer handguards, at certain point you hit the point of diminishing returns. This length maximizes territory for your hand placement and sight radius for irons while also keeping the already comparable hefty weight down.


  • 13.5” Handguard: This length once again cuts down on the weight. If you’re like me, a relatively averaged height guy, your hands probably won’t reach much beyond 14” on a handguard without becoming Stretch Armstrong. So for that reason, unless you need to really push your Iron Sights way out there, this is a great options to cut down on the length and weight.

16” Barrel: Civilian Standard

HWK 15

HWK 15" M-Lok handguard on a 16" Barrel

  • 15” Handguard: This covers most of the 16" barrel and should end just prior to the threading for you muzzle device. It also gives you the most length for hand placement or area to mount things like Angled Forward Grips, hand stops, keymod or m-lok accessories and the like.


  • 13.5” Handguard: A handguard of this length will cover your gas block for the most part, but will cut some weight off the end of your rifle.

14.5” Barrel: Military Carbine/Tax Stamp territory

  • 13.5” Handguard: Covers most of your barrel and allows you to really get your hand placement further out which is advantageous with shorter barreled rifles for recoil control.


  • 12” Handguard: Leaves about 2.5” of barrel out to the world but ditches some of the weight forward of the center of gravity.

12.5” Barrel: SBR Tax Stamp Land

ATF agent meme

Always watching...

  • 12” Handguard: If you’re dipping into this territory, you’re going to be a research guru which you’ll need to be to find the right muzzle device combo (most likely a flash can) with the rail length. If you sort that all out, a 12” handguard will give you the most proverbial bang for your buck as far as your sight radius and hand purchase space.

11.5” Barrel: SBR NFA!

  • 10” Handguard: If you’re running this length, you may be in AR pistol territory. Meaning weight is key and Iron Sight radius isn’t as vital. This length sheds weight.

10.5” Barrels and below:


8.25" RPTR handguard on a 9" barrel

  • 10” Handguard: Gives you the most space for your hand and equipment while maintaining a good sight radius for a 10.5 barrel. You need to be careful on the muzzle device to make sure no muzzle blast is released beneath the rail. A flash can usually works well for this length.


  • 8.25” Handguard: Cuts down a lot on weight while still allowing for accessories to be mounted in multiple spots.


  • 7” Handguard: Gives you just enough real estate for some equipment and your hand. This is for the folks running really short barrels and looking to keep everything as compact and light as possible.


In the end, the best free float handguard length is whatever you are most comfortable with. These are just suggestions but feel free to pick and choose whatever works best for your build.

We also offer a range of M-Lok AR-15 handguards ranging from 7" all the way up to 15". Made in the USA with over 7800+ reviews and backed with a lifetime warranty.

Check out our best-selling HWK Handguard:

STNGR HWK Handguard (7"-15")

from $129.99

Still not sure which handguard is best for you? Shoot us a message and we would be more than happy to talk to you more about your build goals and figure out which handguard is best for you.