DCM-style free float tube for rifle length AR

[Shear_stress]

Got a line on a Colt Sporter Match Hbar, a fixed carry handle A2 rifle with the flash suppressor but no bayonet lug. The price is right but some enterprising former owner replaced the handguards with a set that's compatible with a 37mm flare launcher. Not my style. Since I'm replacing the handguards anyway I thought I'd go one step further.

I like the idea of a ringer--a rifle that looks unaltered but has been subtely accurized. To this end, I'd like to install a DCM-style free float tube that is concealed by standard A2 handguards. There are a bunch of companies that offer these setups: Armalite, Bushmaster, DPMS, RRA, White Oak Armament, etc. Is there any appreciable difference in the accuracy improvement offered by these tubes? Also, is there any real difference in difficulty of installation? I only ask because I recall some nebulous internet post about how RRA DCM tubes are easier to install for some unmentioned reason.

 

[Tirod]

I agree, the use of a free float under the handguards appeals. All the ones on the market appear to be steel, not aluminum, therefore there is a weight penalty compared to any other float tube. Long range precision shooters even have the option of adding a lead weight under the guards to add more.

I'd buy an aluminum one in a hearbeat, already have the handguards in rifle length. In my experience, it would be good having something that would completely eliminate sling pressure from causing a shift in impact - which had caused me to stop using a sling altogether during qualification.

The ones I've seen all go on after the barrel and before the FSB, which makes them less than user friendly to install with an issue front sight.

 

[rskent]

The RRA float tube is indeed very easy to install. It comes with hand guards that are ready to mount. With some of the other tubes you have to take out the heat shields and modify the ends to fit the new tube.

If you use a shooting sling, the difference between using a float tube and just regular hand guards is pretty dramatic. I went from having a different zero in every position to having just one.

Good luck
Steve

 

[Shear_stress]

Thanks for the good info. How about the DPMS tube? It also comes with a set of handguards and swivel rivet?

 

[MetalHead]

I put together a CMP style upper using a DPMS tube a few months ago and I have an unused Rock River tube sitting around. The DPMS sling attachment point is under the front cap instead of projected forward like the RRA, means you don't have to grind off the sling attachment of the FSB. The threads are finer on the DPMS as well so setting the right length so you hand guards fit nice is easy.
My DPMS from Midway came with black hand guards, I didn't get a pin but maybe it got lost, no mater as I will use a roll pin.
That said these are both great units and for a total "sleeper" setup the RRA would be the kitty's fuzzy keister.
Will have in a few days one from Armalite, with my buddy's discount it was less than 85 bucks.

 

[Shear_stress]

The DPMS sling attachment point is under the front cap instead of projected forward like the RRA, means you don't have to grind off the sling attachment of the FSB. The threads are finer on the DPMS as well so setting the right length so you handguards fit nice is easy.

Great information. Looks like the RRA unit requires you to permanently modify the front sight base. I guess they do this so the sling swivel looks like it's attached to the FSB, conforming with DCM rules that mandate that the gun has to look like a regular A2 service rifle.

I'm not sure I want to permanently modify the rifle, though. Looks like the DPMS tube might be the ticket in that case. Gun Parts Corp is blowing them out for $100 on Gunbroker.

 

[MetalHead]

Well the Armalite tube is here already! looks a lot like the DPMS except...... it requires a tweaked gas tube, which comes with it, the sling loop is already installed, they even included the roll pin for the gas tube, also got a Armalite two stage trigger, will be testing it against a couple of RRA two stage triggers shortly, the Armalite is a good looking unit, but hey when shooting you can't even see the trigger, it's how it feels.

BTW, also unlike my DPMS or RRA, the Armalite did not come with modified handguards, but they do offer them at reasonable cost, fine by me as I wanted olive green and they only had black.

 

[Shear_stress]

I live pretty close to a shop nationally known for doing machine work on ARs. On a whim I gave them a call. They sell the RRA float tube with handguards and will install it for free--including cutting the swivel off the FSB! Pretty convenient, as I don't have a good vice or receiver block.

While the barrel and flash hider are off I may have them do a target crown as well, though I'm not sure how that will work out with the chrome bore. The chrome itself hinders ultimate accuracy, but I'm not enough of a rifleman to tell. The "stealth" float tube and a Bill Springfield trigger job will probably get me most of the possible accuracy improvement--within the limits of my ability, anyway.