Free float hand guard accuracy

[seabassnfg]

I am planning my first AR-15 build and was researching free float hand guards. Alot of sources state that a free float hand guard improves accuracy because it doesn't allow the barrel to flex when the hand guard is resting on or against a surface. I understand that, but..

Does the accuracy of the gun now rely on how perfectly the hand guard is installed on the rifle?
If the hand guard is a little crooked, that means the sight at the hand guard will now be crooked..

Am I correct in my thinking? And is a free float hand guard still worth it?

Thanks in advance for the help

 

[gmcttr]

A free floated hand guard makes a big difference if you are applying lots of pressure to it through a sling as one would in certain types of competition shooting. Not so much if only the weight of the gun is rested on it.

As to the sight, if the hand guard is securely installed, 'sighting in' corrects for any slight misalignment. Sights can also be part of, or mounted to the gas block.

 

[jrh84]

If your front sight is mounted on the handguard, and that handguard is installed crooked or can flex, then yeah, getting zeroed might be tough. If it's installed correctly, the average Joe shooter probably won't be accurate enough with irons to see the difference of a couple thousands worth of flex at the end of the handguard. A decent irons shooter would.

If you're running a receiver-mounted optic or a gas block mounted front sight, the handguard can be as crooked as you want and it won't affect anything, as long as you're not contacting the barrel.

I shoot high power across the course. When my free float tube contacted the gas block, my groups were roughly 3-4 moa (all over the 8 ring at 600 yards). After reinstalling everything and making sure there was no interference, it went back to <1 moa elevation. My wind calling was a different story.

In short, if you're serious about accuracy with your AR, yes, a free-floating handguard is important (probably the biggest factor in AR accuarcy, to be honest).

 

[Alpo]

All good info; however, for what it's worth, an F type A2 front sight is likely never to let you down in times of hard use. Milspec handguards or MagPul generally insulate against heat from the barrel in rapid fire situations.

It all depends on what you want. And one AR is never enough! My go to AR15 is configured as stated in the first paragraph.

 

[seabassnfg]

Awesome, thanks for the info everyone.

I was planning on having a full length free float hand guard. So ya, my front sight would be mounted to the free float hand guard. I guess I would just have to make sure install is perfect, and sight everything in..
I just wonder how much abuse the free float hand guard can take before it starts moving and affects accuracy.
Does anybody know of any free float hand guards that are known for their reliability / quality?
I was thinking about the bcm kmr

 

[Vigilant]

Awesome, thanks for the info everyone.

I was planning on having a full length free float hand guard. So ya, my front sight would be mounted to the free float hand guard. I guess I would just have to make sure install is perfect, and sight everything in..
I just wonder how much abuse the free float hand guard can take before it starts moving and affects accuracy.
Does anybody know of any free float hand guards that are known for their reliability / quality?
I was thinking about the bcm kmr

BCM MCMR.

 

[seabassnfg]

BCM MCMR.

Because of the mlok, as opposed to key mod?

 

[Vigilant]

Yes.

 

[russc2542]

The free float thing has as lot to do with harmonics and consistency than the weight of the gun "bending the barrel". Thing of the barrel as a tuning fork, every time you fire a round is like tapping the tuning fork. if you hold only the base it gives the same frequency every time... when using consistent ammo, the barrel will be in the same point of the oscillation as the bullet leaves the barrel. If you have anything touching the fork (like a handguard mounted to the gas block on one end) you change the frequency. If you can put the same object at the same point with the same pressure, you can still have a consistent frequency (think of the frets on a guitar neck and setting tension to tune it) but with a gun barrel, it's hard to put the same force in the same direction that consistently (a sling pulling on the side, gravity on the weight if the gun using a bipod or rest, support hand at the mag-well, etc) so you free-float the handguard and make up for the misalignment by zeroing the adjustable sights. You can still pull the sights out of alignment with a handguard mounted front sight and a gorilla pulling on the sling but a receiver mounted optic or gas-block mounted front sight reduce that to almost nothing.

 

[rvb]

not all hand guards are equal. the mount is the usually the weak link. some can bend and flex with even minimal pressure where you'll struggle to even maintain zero. do your research. for best results have the sight mounted on the barrel (this is how they are used in high-power matches for example, which when folks talk about competition shooting with sling pressure, etc, that's usually what they mean). If HG-mounted irons are your primary sights, then make sure you buy based on rigidness, not looks.

-rvb

 

[rvb]

I was thinking about the bcm kmr

probably good to go. I have a couple. I've put a straight edge along the top of the HG and receiver and not seen movement with moderate pressures....

-rvb

 

[seabassnfg]

Great, thank you for info, everyone. My lower is on it's way. Looking forward to the build

 

[garagegunmaker]

Personally prefer free float handgaurd with an a2 front sight post. That way the sight is always true with the barrel and can’t be moved with sling/rest pressure on the handgaurd, and I can pull as tight as I would like on my sling because it’s attached the the handgaurd. Also with the a2 post you can’t break it and there is no flipping up to mess with. I run fixed rear irons with lower 1/3 cowitness red dots, and folding rear irons on scopes rifles. (Yes I have a2 posts on scoped rifles, it works fine.)