The term “free float handguards” is something you see a lot on “precision” AR-15 builds — guns designed to pluck the wings off a fly from 500 yards. But what exactly do they do? One reader asked about them as a fix for barrels becoming too hot (see Friday’s Ask Foghorn), but that’s not really their intended purpose. Are they useful, or like full length guide rods on a 1911 are they just a way to gouge you for more cash? Let me explain…
One of the first things everyone does when they get a new gun or swap the optics on an existing one is “zero” the gun. The idea is to make the aiming devices mounted to the firearm line up with where the barrel is actually pointing, which enables the shooter to then fire with confidence secure in the knowledge that their rounds will impact exactly where they are aiming. This is also described by some as “aligning the point of aim with the point of impact.”
The issue with firing accurately at distance is that even the slightest changes in the alignment of the barrel can throw the round way off target. Even though barrels are typically made of hardened steel and other tough stuff the fact that they’re rather long allows even minute forces to act on them like a lever.
Using a barrel that hasn’t been free floated means that every time you change the forces working on the barrel, whether that comes from resting the forward handguards on a stand or simply gripping the handguards differently the barrel will bend and the bullets won’t necessarily go where you wanted them to go.
As the barrel heats up the stock will continue to press on the barrel and throw the rounds off even farther, meaning even if you never change how the gun rests or how you hold it the rounds are still going to spread out worse than they should.
Free floating the barrel is the solution to this issue. On a traditional rifle (such as a bolt action Weatherby Vanguard) a sufficiently rigid stock must be selected and material must be removed from the stock forend (around the barrel) until the barrel no longer touches the stock. The standard test for if a barrel is free floated is the ability to run a dollar bill between the stock and the barrel all the way to the receiver.
On an AR-15, the handguards need to be designed in such a way that they mount to the receiver instead of the barrel (as traditional handguards use a device near the gas block to hold the far ends of the handguards). Once this has been done the barrel “freely floats” fully independent of outside forces pressing on it.
Naturally this puts more stress on the receiver (as it now needs to support the weight of the entire rifle) which leads to things like “aluminum bedding” or “(fiber)glass bedding” for the receiver which provides a more solid way to marry the metal and wood portions of the firearm.
Free floated barrels do in fact lead to smaller groups.
As a perfect example, I was shooting my Weatherby Vanguard yesterday with its brand new free-floated stock and my groups were at least 1/2 the size they used to be with the non-free floated factory stock. One simple change (that cost less than $100) made the difference between 1.5 and 0.5 MoA groups at 100 yards.
Some firearms are more expensive to free float than others, but thankfully there are free float options available for the AR-15 system for less than $50, and “good” ones are available for less than $100.
If you’re a serious shooter then your rifles should probably have free floating handguards, and especially with the low associated cost I can’t think of a reason not to. Even so, I like to keep at least one cheap “standard” AR-15 16″ upper laying around to try out new stuff and let the newer shooters use. At the end of the day it all boils down to whether the expense is worth that extra accuracy, and for me it mostly makes sense.
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I think this is the first article on free-floating that I have read that hasn’t mentioned barrel harmonics. The largest and greatest advantage of free-floating a barrel is that you allow the barrel to vibrate and move unrestricted. Older firearms like the MkIV Enfield are hampered because the barrel is secured to the stock and therefore it is not allowed to vibrate freely but instead the vibrational force is directed towards the mussel causing the very end of the barrel to move in a greater circular motion; which is why you will never have a .303 Enfield with a 1/2 MOA, the same with AK pattern rifles as well. The more points of pressure and the further up the barrel the greater the vibrational arc will be when the rifle fires. Free-floating allows the entire to barrel to move and vibrate as one. The heavier the barrel and the less points of contact it makes with the stock means that the mussel arc will be smaller and groups will be tighter.
You’re absolutely right about barrel harmonics, but I wanted to keep the technical jargon to a minimum and so left it out of the article. Barrel harmonics (IMHO) are complicated enough to deserve their own article, and I’ll link that in here once I write it. Eventually. One day.
If your going to be speaking to barrel harmonics, you might as well mention the beneficial effects of properly tensioning a thin light contour barrel by contact with the stock. For most of the history of firearms manufacturing, the barrel was no heavier than was necessary to properly contain the combustion gases, as firearms were meant to be portable weapons, not the heavy bench slugs we see today. Historically, barrels were also very long, 30″ plus, compared to what we use today, due to the powders available. Part of the stock’s original job was to tension and support consistently the barrel and to dampen the high harmonics that a light long barrel would experience. This tension can reduce group sizes, sometimes at the cost of POI shifts with big environmental changes. What’s the practical use of this info? If you have a 26″ light sporter think carefully before you go to the trouble of free floating the barrel, you could open up your groups. There is a reason most factory stocks have a contact point far up the barrel.
“The more points of pressure and the further up the barrel the greater the vibrational arc will be when the rifle fires.”
I always thought it would it increase the frequency of the vibration, not the amplitude. Am I mistaken? And if you dont want a point of pressure near the muzzle, than can you explain the barrel tuning accessories which apply pressure near the muzzle?
Mussels are what you eat. The muzzle is where the boolits come out. ;>)
Mr Smartipants
I think the “Free Float” craze in AR style rifles is a little over blown.
Yes they do increase accuracy. As such, they are a great addition to a 20″-24″ heavy barrel varmint AR with a high power (4-12, 4.5-14) optic intented for long distance, accurate shooting.
However, on a 16″ (or shorter if you have an SBR) carbine with a light weight or, god forbid, AP4 contour barrel and only a red dot mounted on it. A free float handguard will do nothing but cost you money. What is the point in cutting a 2″ at 100 yds group to a 1.5″ at 100 yds group when the dot in your optic is 4 MOA?
It can have a much greater effect than that, on a 18″ RFB, loading a bipod can change the POI by 4-5 inches at 100 yards when compared to the POI from a lead sled. On a non-bullpup rifle, where the barrel acts a really long lever, I could see it having a greater impact on POI.
http://www.thektog.org/forum/showthread.php?t=243381
Big J you are wrong. Free floating a hand-guard on a modern AR-15/M-16 platform rifle makes sense as it does indeed make a difference. I can illustrate this point by using cover and supporting the rifle hand-guard on the cover ( say a barricade as an example) the pressure exerted on the hand-guard does transfer to the barrel and can move the POI. I have seen this demonstrated during training. You might get away with this at 25-50 yds, but your POI can shift dramatically at distance.
I have an AR carbine with 16 inch barrel free floated. I realize at that length free floating may be redundant but I like how it looks and feels, everything else on the gun is set up like a full length rifle though.
I do agree that it is a bit of a fad for most people though. Like Big J said if you are going for a light barrels and low power optics save a few bucks and get a regular handguard.
I bought a used ar a3 with a free float grip and a bulled barrel and its very accurate but theres alot of vibration in the floating grip when I fire. Is ther any grips that eliminate this?
All of the above is good information, however the free float can make a remarkable difference when shooting for competition, it will make little to no difference to the average shooter! I was in the USMC and with a simple GI M4 carbine with a non floated barrel I could hit a 10in target 10 out of 10 times from 300yrds and at 500 yards the silhouette of a man 10 out of 10 times in a wind storm on a rainy day!! So if you are shooting for competition and the smaller group may decide the outcome of the match then by all means free float your barrel! Other wise save yourself some money and get traditional hand guards that will suit just fine for home protection or backyard target practice!
All of the above is good information, however the free float can make a remarkable difference when shooting for competition, it will make little to no difference to the average shooter! I was in the Marine corps and with a simple GI M4 carbine with a non floated barrel I could hit a 10in target 10 out of 10 times from 300yrds and at 500 yards the silhouette of a man 10 out of 10 times in a wind storm on a rainy day!! So if you are shooting for competition and the smaller group may decide the outcome of the match then by all means free float your barrel! Other wise save yourself some money and get traditional hand guards that will suit just fine for home protection or backyard target practice!
good point. hoorah!
i have a 303 bsa no1 mk 111. when i bought it it alreddy sporterized with shortened stock. i free floated the barrel from the chamber to the front. will it still be able to shoot good groupings because everybody is telling me that the 303 bsa is a very accurate gun and exelant for hunting. i will wait for your reply. thanx
This is a great article! very well written. I have a quick follow up question… I have an ar15 with a 14.5 inch, GI profile, free-floated barrel. there is very minimal space between the gas block and free floating handguards, but it is free all the way around. 1.) Is this sufficient? If I understand your article correctly, the accuracy of a barrel with touching handguards is affected before the trigger is pulled, due to the forces the user places on them by resting it or gripping it. so, though my handguards afford me minimal space between the gas block and guard itself, as long as they do not contact one another, the barrel is unaffected until I pull the trigger… am I seeing this right? 2.) that being said, once the round is fired, and harmonics do their thing and move the barrel, do I need to be worried about the gas block striking the inside of the handguard? will this do any damage to the barrel or receiver at the contact point of the barrel? will this be sufficient enough to knock my sights out of alignment?
I come from a military background and have pretty extensive experience with m16s and m4s. from the 60 or so rounds I’ve fired from my ar in this configuration, all seems to be in good order. but I really wanted to get your take on this. thanks for your time and assistance!
Nick Leghorn, you mention that “there are free float options available for the AR-15 system for less than $50, and “good” ones are available for less than $100.” Can you elaborate?
I have a frankengun built by a friend fortunately from quality components. At 100 yards, I saw groups not better than about 2 MOA.
Then I installed the Daniel Defense two-piece, drop-in, free-float handguard and my POI for three shot groups at 50 yards all touch one another…ON IRONS AND NOT ON MAGNIFIED OPTICS.
I haven’t fired at 100 yards due to range crowding. But it’s coming.
The free-float handguard also dramatically improved my offhand shooting to the point that all my rounds from a 10 round grouw at 50 yards are now in the 9 ring.
Get ya some.
Best,
LF
I started with a A4 20″ rifle. I replaced the heavy barrel with a pencil barrel. The front sight block that came with that vibrated loose when shooting NATOs, so I replaced that with a low profile gas block. I replaced the iron sights with EOTech with multiplier. I just ordered a M4-72 muzzle brake and a FM-9 15″ free float handguard.
I shoot at least 100 rounds every time I go to the range (a couple times a month).
My question: where should I put my support hand? I never use sandbags, a bipod, etc. I just support with my elbows with my support hand as far out on the A4 handguards as possible. My finger touches the front of the triangular handguard cap. But when I replace the A4 handguard with the 15″ free float, will I need to move my support hand back closer to the receiver? The free float will attach with only a barrel nut. Won’t the handguard bend or something if I’m gripping it 15″ from the attach point?
I’m replying to my own question. I found that the free float and its attachment were so sturdy that it easily supported my rifle even with my support hand all the way out on the end.
As far as bolt action hunting rifles go my experience is more often than not they will shoot best with a little pressure against the barrel from the forend of the stock. Not an issues with a synthetic stock as far as temp and humidity changes that can effect wood stocks. However some, especially heary barrels will often shoot better free floated. The most accurate three bolt rifles I own all have pressure contact on the forend against the barrel. All three shoot under 3/4 moa and one will shoot under a half moa with two different hand loads. These are are factory Remington 700s. I’ve free floated the barrel on two of them and accuracy went to hell. Likely this is due to changing barrel harmonics not liking the the particular loads that were accurate when the barrel was bedded.
Want to know if your bolt action rifle will shoot better with a free floated barrel without doing permanent changes? Remove the stock and put a shim (plastic like credit card thickness)between the stock and action just behind the recoil lug. Use a washer type plastic shim (same thickness as front shim) for the rear action bolt. Tighten action/stock bolts and check for contact between barrel and the barrel channel on the stock. Shoot and see if groups improved or got worse. Based on outcome one can keep the barrel bedded or open up the channel and free float.