I am building my first AR and would like to build a carbine that is robust, yet very accurate. I would eventually like to mount an IOR 4X M2 scope on the rifle. I currently have a 15" RRA barrel (chrome lined) with a permanently attached A2 flash hider on it.

How much more accuracy could be expected by mounting a free float tube (i.e., MI 2 piece free float) compared to a standard 2 piece non-free float rail?

Thank you for your advice!

The more experienced people on the board would say that for couch commandos like myself, the amount of change in accuracy would be very minimal. However, for shooters where the fraction of an inch is critical - this is crucial.

I would worry more about a barrel being properly crowned. That would really mess up your accuracy.

Good luck.

FreeFloating ARs came about from competition shooters that use a sling, properly.

Save the money for other stuff on your carbine.

Dave S

Aluminum free-floating handguards heat up real fast.

Quoted: Aluminum free-floating handguards heat up real fast.

They also allow the barrel to cool better, preventing cook offs.  I use a pencil barrel and I shoot both rotations when I take a class.  That means up to eight mags as fast as I can fire failure drills.  Shit gets hot.

Huh? You got it backwards bub. They absorb heat slower because nothing is touching the barrel. They are generally about a .25" to 1" off the barrel, depending on the manufacturer. Some are even wider. Regular handguards or other rails that touch the barrel draw heat faster.

I can dump multiple mags on my Larue 9" FF rail and Predator P9X FF rail uppers, grab the rail immediately afterward (without rail covers) and it is just a bit warm.

You can't do that on rails like the SureFire M73 which are not FF. They draw heat much faster, and will smoke after a mag dump or two.

As far as the original question, yes they improve accuracy because there is no added weight drawing down directly off the barrel.  They also generally make the upper lighter.


- rem

Quoted: Aluminum free-floating handguards heat up real fast.

he is speaking of the Al free float tubes that lack any ventenlation slots or thes m1913 rails.

ps if your going to use a bipod freeloat tubes well help.

FWIW, in my testing years ago using several brands of rifle, (RRA, Bushmaster, Colt) just free-floating the barrel using an ARMS S.I.R. #45, (replacing the standard handguards) generated about 1/16" tighter groups on the Bushmaster (14.5", 1/9, w/ perm. AK brake, chrome lined) and the RRA (faux 16", 1/9,  M4 barrel, chrome-moly).

The Colt barrel(14.5" 1/7 w/ perm. Vortex, chrome-lined) exhibited no measurable reduction in group size.

Note: testing involved Q3131A, & Fed GM 69grn. SMK, 5 shot groups of ea., before and after S.I.R was installed.

Mike

Free float tubes don't really make the barrel 'more' accurate.  Inherent accuracy is already there.  The free floating allows less things to affect the barrel thus allowing you to shoot it to it's full potential.  Things like pressure from the sling, bipod and weight of anything mounted to rails etc can affect accuracy, free floating allows nothing to influence the barrel..

If you are making a long long long range SPR-ish type rifle a free-float hand guard is what you need.
Items like a sling or bi-pod will put pressure on the barrel end allowing it to move/shift a hair or two, if using
a free-float tube this doesnt mean anything to you. If using regular type hand guards, a hair or two could mean
inches off your target down range, this is hundreds of yards down-range though.



I use a ultra-light YHM free float tube on my M4gery for extras to be put on at all angles, like VFG (bottom), lights (sides)
and optics/sights (top).

IMHO the essentials to AR accuracy  are #1 a good barrel, #2 the right ammo and #3 floating the barrel. THEN you gots to shoot it right............
ETA : but they DO add weight. There's a trade off to most everything.

Benifits of a Railed Free Float outweigh not having one.

For most shooters, they can't tell the difference.
If your handloading and want the most out of you AR then FF is the way to go.

I have a free float on my CMP Service Rifle where we sling up tight and shoot out to 600 yards.
On my 14.5" IPSC gun I feel that a free float tube is good for getting rid of excess cash. With that short of a barrel I would be very surprised if there was any noticable difference. If you are going for the cool factor then there are some cool looking free floats out there as well as some equally cool non-free float tubes.

In order of my perceived importance on a 14.5" gun it is:
1) A lot of pratice
2) A good barrel with Eye-Spy's mentioned target crown
3) Good ammo
4) A great trigger
5) A good optic
6) a free float tube

Bill