AR 15 Hand guards: Standard or free float?


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CDR_Glock
February 16, 2011, 07:11 AM
What do you prefer and why?

I just had a quad rail free float installed. Had to remove my front iron sight and replaced the gas tube. I haven't tried it, yet.

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cfullgraf
February 16, 2011, 07:16 AM
AR-15s with free float hand guards have more accuracy potential than those with standard hand guards.

Zerodefect
February 16, 2011, 08:03 AM
12-14" Larue or DD Lite rails. Larue for carbines, DD for heavier rifles is my preference

I like to reach out further so I can steady my aim better, and reduce mussel rise. No bench shooting for me.

Mags
February 16, 2011, 08:19 AM
Another benefit of floated rails vs non FF is that optics can be mounted to the forearm rails with no shift for the point of aim.

Which brings up this question.

Are KAC RIS rails floated? I see optics mounted to them all the time but they attach like a regular 2 piece with the delta ring.

Tirod
February 16, 2011, 08:50 AM
Free float handguards only preserve the inherent accuracy of the barrel by preventing outside bending forces moving the point of impact.

They cannot and will not make a 2MOA barrel suddenly start shooting 1MOA. It's not possible. What is implied by saying they make a gun more accurate is that the shooter was using it in ways that made it less accurate. Tight slings, resting an exposed barrel on objects, and not using one consistent holding technique will cause the point of impact to shift.

Technically, it's still as accurate as the barrel and load can be - as long as you keep that pressure on it. Military shooters know that sling swivels attached to barrels require consistency to maintain the point of impact. What happens with most shooters is they are inconsistent, sometimes for good reason.

Also factor in the actual need for high precision - on a prairie dog rifle, it's much more desired. On a tactical/duty gun - or hunting medium game in North America - 2MOA is all you need out to 500m.

To make a specific gun more accurate, the barrel, ammo, and sights would have priority. The barrel obviously needs to actually be as accurate as needed, ammo with the minimum group size selected, and a scope chosen that will work with all the ranges needed. Only then will a free float give an benefit. Given run of the mill barrels, ammo, and sights, I seriously question why the money was spent for accuracy. Utility, rails, or looks, yes, thats why the Army put a KAC quad rail on the M4. It doesn't make it suddenly shoot 100% more accurately, tho. At least, no ones bothered to point that out the last ten years.

There's little to no documented improvement in accuracy with a free float, although there is a lot of word of mouth. For the expense - $250 is average - a lot of shooters would do better with a quality optic first. Once the barrel and ammo are brought up to the requirement, it will still attach to the rail, and the shooter can then discover whether it's the lenses or their skill holding them back.

That takes a lot of ammo at the range, which is what the effort is all about, high precision shooting, not actual tactical or field game use.

kwelz
February 16, 2011, 09:30 AM
Rails offer far more benefit than just accuracy. In fact a standard AR shoots better than most shooters are capable of. Most shooters I have seen have trouble taking the center out of a target at 25 meters, forget 100!

Zerodefect
February 16, 2011, 09:47 AM
Another benefit of floated rails vs non FF is that optics can be mounted to the forearm rails with no shift for the point of aim.

Which brings up this question.

Are KAC RIS rails floated? I see optics mounted to them all the time but they attach like a regular 2 piece with the delta ring.


You shouldn't mount your primary optic anywhere on the forearm unless it's a monolithic 1 piece upper reciever. Larue makes cantilever mounts that stretch out over the rails if you need your optic far forward. I use a cantilever mount with my Aimpoint Comp M3, and my Trijicon 5-20x 50mm scope.

You can mount a backup optic on a rail, but I'd avoid putting the primary on one.

Rails have a ton of flex. Grab a rifle by the rail, with a good rail like Larue or my DD Lite 14", push the barrel sideways, the rail bends, you can see it get close to the barrel and spring back. A perfectly rigid rail would be Heavy.

If your push/ pulling or holding the float tube down on something it's flexing. Which is why it's good that it free floats, it flexes, not your barrel/reciever.

Welding Rod
February 16, 2011, 03:34 PM
Depends on sights. I prefer plastic handguards for their feel, but like floating for accuracy.

A1 / A2 Irons - Plastic Handguards
Low Power Optics -Plastic Handguards
High Power Optics - Float

ForumSurfer
February 16, 2011, 03:40 PM
I put magpul moe handguards on my ar15 when I built it because they were part of a kit. I've yet to free float it because the moe's are so comfortable when shooting.

Kwanger
February 16, 2011, 04:19 PM
Another benefit of floated rails vs non FF is that optics can be mounted to the forearm rails with no shift for the point of aim.

Which brings up this question.

Are KAC RIS rails floated? I see optics mounted to them all the time but they attach like a regular 2 piece with the delta ring.
That's not right. If you have an optic mounted on your free float rail and you then rest that rail on something/crank on it with a sling, the rail will (potentially) move....and your optic with it, while the floated barrel remains stationary. Totally defeats the purpose of free floating.

Mags
February 16, 2011, 05:11 PM
What about irons mounted on a FF rail?

Apparently none of you guys have seen any military rifles. They use the KAC RIS and they mount their Aimpoints, Acogs, PEQs, etc... on the two piece KAC.

Zerodefect
February 16, 2011, 06:00 PM
What about irons mounted on a FF rail?

Apparently none of you guys have seen any military rifles. They use the KAC RIS and they mount their Aimpoints, Acogs, PEQs, etc... on the two piece KAC.

Just because the .mil does it deosn't mean it's good.

Even with a monolithic rail,you need to keep your primary optic back over the main body of the reciever.

BUIS are just for backup so we deal with those. Just remember you can't use a wall/tree/doorway press on the front rails when useing your BUIS. Not a big deal, I've only used my BUIS in practice only. Never in competition, never in the field. My SPR deosn't even have BUIS.

I think I can get some pics to illustrate how much flex even a top $$$$ rail has if you guys want.

mshootnit
February 16, 2011, 06:08 PM
Depends on sights. I prefer plastic handguards for their feel, but like floating for accuracy.

A1 / A2 Irons - Plastic Handguards
Low Power Optics -Plastic Handguards
High Power Optics - Float


I think that's about the perfect summation.

HOLY DIVER
February 16, 2011, 07:19 PM
i don't really see the need for a FF tube on a 16" carbine but i do feel a FF rail i a more solid than the 2piece non FF rails so IMHO if i wanted a rail on my carbine to mount a vertical grip I'd use a FF rail just because its solid (prob would use LARUE) I was thinking of getting a Yankee hill but the more i think about it the extra$ for the Laure is worth it. i guess what I'm trying 2 say is if you need a FF for shooting paper @ 600yds u need a 18-20" barrel this is just my opinion

Kwanger
February 16, 2011, 07:41 PM
What about irons mounted on a FF rail?

Apparently none of you guys have seen any military rifles. They use the KAC RIS and they mount their Aimpoints, Acogs, PEQs, etc... on the two piece KAC.

Hmm, apparently I have not. Well, if you discount the 12 years of being behind a military rifle, that is. I seem to recall most of them having a front sight post that is fixed to the barrel, not a free float rail.....

but that is all besides the point. This is not a "belief" question, it is a fact. irons on a front free floated rail, optics on a free floated rail - makes no odds, simple fact of the matter is, if the rail moves due to external influences, so does whatever is mounted on it. The nature of the free float means the barrel does NOT move with everything else. Think about it. Its not like this stuff moves a lot - but it can move nonetheless, and back to my point - defeats the purpose of a free float rail. Keep your optics on the receiver.

Kwanger
February 16, 2011, 07:42 PM
Just because the .mil does it deosn't mean it's good.

Even with a monolithic rail,you need to keep your primary optic back over the main body of the reciever.

BUIS are just for backup so we deal with those. Just remember you can't use a wall/tree/doorway press on the front rails when useing your BUIS. Not a big deal, I've only used my BUIS in practice only. Never in competition, never in the field. My SPR deosn't even have BUIS.

I think I can get some pics to illustrate how much flex even a top $$$$ rail has if you guys want.
Monolithic - I would argue that would be an exception.

And you are right about BUIS - they are exactly that - but I wouldn't go so far as to say you can never rest the rail on anything (I'd take a quick rest on anything if available any time over an offhand shot, which will induce more error than the rest, no matter what your setup!), it is just a good idea to be aware it may influence your shots, that's all, so you should try not to apply undue pressure. I had great results this last weekend in a action rifle match using rail mounted BUIS resting on field expedient rests - but was aware of the issue so didn't force the rifle against anything.

Dr.Rob
February 16, 2011, 08:04 PM
Standard handguards. I might move the side mounted sling swivel to the standard placement.

henschman
February 16, 2011, 08:18 PM
I like a FF rail, but I like my front sight attached to the barrel instead of the rail.

I don't consider my iron sights to be "just for backup"... I like to think that they are potentially my primary and only sighting system.

I like a long rail so I can have plenty of room to get my support hand where it needs to be, for any style of shooting. For close quarters, I like my hand very far forward for better muzzle control. For sling-supported precision shooting, I still like my hand pretty far forward, against the front sling swivel.

Just one more reason I prefer a 20" barrel... longer sight radius, and you can stick a decent length FF tube on it while still keeping the gas block mounted front sight.

I really like the Midwest Industries SS free float tube. It is the lightest you can get, and you can put rails just where you want them or not use them at all.

I also see that Troy is now selling their TRX Extreme rails for .308 ARs... if I build that MA-Ten, I might have to look into the 12" model. That would go nicely over a 20" barrel.

Mags
February 16, 2011, 08:31 PM
Hmm, apparently I have not. Well, if you discount the 12 years of being behind a military rifle, that is. I seem to recall most of them having a front sight post that is fixed to the barrel, not a free float rail.....
Currently on my 10th year on active duty, I don't see where I mention irons on the KAC RIS. Here let me show you what I posted.
What about irons mounted on a FF rail?

Apparently none of you guys have seen any military rifles. They use the KAC RIS and they mount their Aimpoints, Acogs, PEQs, etc... on the two piece KAC.
See the break in the two statements that means they are two different unrelated statements.

Our current M4s have the PEQ which is our primary night optic mounted on the KAC RIS. That is a fact from a current military member. Some guys extend their Aimpoints over the KAC as well.

My real question was is the KAC designed for this purpose, is it special in that it is more ridgid?

Kwanger
February 16, 2011, 08:44 PM
As stated, with a decent FF rail, the movement will be pretty minimal anyway - but it doesn't mean it is the way to go. I don't have any experience with the KAC rail, although my POV is that anyone who extends an optic onto their rail is, by default, losing their Free Float advantage. As you will know - not everyone in the military is really a gun guy, or really thinks through all this stuff.

Mags
February 17, 2011, 06:37 AM
I don't have any experience with the KAC rail, although my POV is that anyone who extends an optic onto their rail is, by default, losing their Free Float advantage The KAC is not a free float, thus my whole question regarding it. I already posted this earlier in this thread but the KAC attaches like standard handguards using the delta ring.

The PEQ is supposed to be mounted on the forearm rail it is not up to the member.

Tirod
February 17, 2011, 08:28 AM
Let's remember that the military adopted rails for mounting various types of optics, lights, lasers, etc for a large and diverse user base. It's a basic assumption the weapon is a standard 2MOA chrome barrel with service ammo, effective range is 500m or so.

That's a 10 - ten - inch group at 500. Good enough for hunting and combat. If you want a 3" group at that range, a free float will only help if the barrel, ammo, optic, and shooter can deliver it all up first.

That's the whole message left out of the marketing hype on free floats, and the myth of military spec gear. It's NOT always hyper cool accurate, in this case, it's an institutional compromise - mount a bunch of stuff on the weapon by a lot of different users.

As most of us prior service are very aware, all that rail space isn't locked up with a lot of dead weight gear that isn't mission essential. Nobody wants to carry a 12 pound combat carbine, even KAC is in print saying the average civilian shooter has no good reason to have one. Most of the real world pics of troops in the box show empty rails. Most of the ads hyping the merchandise show photogenic aryans with leading edge kit and loaded rails. Yes, I'm calling out the race card, the Army has a significant number of other ethnic groups well represented. If the pic doesn't show skinny young under 23's with an integrated team, IT'S HYPED ADVERTISING, official or not.

The weapons in that pic are then subject to enhancement for the photo shoot, not what real troops use for that situation in their daily mission. If it's a high noon photo, how many times do you see NVG's, laser's, and VFG's mounted up? Complete BS, the gear is stowed in the pack to protect it and keep it dust free.

Same people who shoot for Nike shoot for the military equipment ads. If that sounds a bit cynical, it's coming from a viewpoint not blessed with being dropped off at the Mall with Mommy's debit card. When every single piece of kit comes from a shooter's own blood, sweat, and tears, you get serious about what it really delivers.

Rails/free floats have not MOA improvement guarantee, it's significant because it's never mentioned in the ads. Just blonde haired blue eyed buffed out thirtysomething psuedo warriors posing with the tricked out goods. :rolleyes:

Mags
February 17, 2011, 08:35 AM
Good post Tirod, but a lil weird...

kwelz
February 17, 2011, 08:46 AM
even KAC is in print saying the average civilian shooter has no good reason to have one.

Some gun companies said the same thing about 30 round magazines.

I agree with you in general but I see you post this a lot and I just disagree with it very strongly. Rails offer a number of advantages. Only one of which is mounting things to the rifles.

I would never own a weapon without a rail now. Not because I need to mount 50 things to it but because of the other benefits offered by them as well.

Advantages of a rail:

Mounting availability
Improved accuracy
Ability to use a proper grip on the rifle. (Longer rail over or wrapped around the Front sight.)
Keeps more heat away from the shooter


Any one of these may not be enough to justify the rail. But put them all together and things change.

Now with cheap rails you have to worry about weight. However quality rails alleviate this problem. Standard M4 handguards with a Delta Ring weigh about 9oz.

A 13 inch Troy TRX extreme rail weighs about 11.5oz. So to add 6 inches or grip, better heat dissipation, free floating the barrel, and the ability to add lights, etc, you are only adding 2-3oz. And the rail costs less than $200

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