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Questions about Quad Rails, free-float vs. drop in, plus front sight post?

Discussion in 'Black Rifle Forum' started by ScrappyDoo, Jan 16, 2011.

  1. ScrappyDoo

    ScrappyDoo Tacticool brah!

    Jan 16, 2010
    Hi ,

    I am now thinking about a quad rail for my new Bushmaster 14.5"/1.5" AR. It came with a tri-rail-"gasblock" and tri rail "hand guard". I decided to get a Magpul handguard so I removed the tril-rail handguard to put the Magpul on. After an hour of fighting with not being able to get the Magpul on, I realized I had to get the tril-rail gasblock off to install the Magpul handguard. So now I took them all off and have the Mapgul carbine handguard on there, but I am thinking about getting a quadrail.

    So what would be the different of a drop in vs. free float? I guess I read that a drop in, would be easy to install and I could do that myself (just like installing the handguards) but the free-floats need to be installed professionally? But they're better because they free float the barrel? Also I was looking at all the different ones on Primary Arm's website... And they had a Daniel Defense one, but then they had a Daniel Defense one that's larger for including the front sight block... Now which one would I need? I have a front sight block ,so I would need the larger diameter one? Basically, I would like a Daniel Defense one, could someone show me which one I would want (For a Bushmaster carbine ) ... and installation tips/? or best left to professionals?

    Lastly, it has *crossed my mind* about the piston retrofit, Bushmaster has a gas piston retrofit kit... But i noticed it includes new handguards...and I saw a quad rail that referenced (for use with gas piston ars etc.) so would that mean if I got quad rail, then got agas piston ,I would need a different handguard/quadrail to take into account the gas piston retrofit kit? Sheesh this is confusing. Thanks to all for the help.
  2. The advantage of a free float rail is that they don't attach to the barrel, allowing it to flex and bend when fired without interference. The advantage of this is accuracy. For a precision rifle it's a must, for a fighting carbine not so much.

    Drop-ins install just like the standard handguards utilizing the delta ring and handguard cap. They are generally non-free float. For a good drop-in rail I recommend the Troy MRF-DI, it's rock solid and reasonably priced. The KAC RAS is another great drop in non-free float, it's the standard issue rail for the military M4, but is very pricey for what it is. You can find some good deals if you look around though.

    Free float rails are typically more difficult to install, usually requiring a gunsmith/armorer unless you have all the proper tools and know how. Free float rails are also considerably more expensive. If you have a permanently attached muzzle device, you can rule out several of the one-piece free floats as they require removal of the muzzle device to install. There are many many good ones, Troy, LaRue, Daniel Defense, and MI all make high quality rails systems.

    There is one exception to the above, the Danial Defense Omega rail. It is a free floating drop-in rail, no gumsmithing required. A little pricey but an excellent product.
    Last edited: Jan 16, 2011

  3. oops.
    Last edited: Jan 16, 2011
  4. ezterra


    Mar 2, 2005
    Eglin AFB, FL
    Things may have changed now since I last looked into quad rails, but when I was looking several years ago, I went with a FF not necessarily for the accuracy advantage but because it had a much more secure mount. For instance, my issue M4 with non FF quad rail has quite a bit of wiggle to it. Whether this is a practical issue or not, I don't know. However, it bothers me enough, at least mentally, that I have FF rails on my 2 personal ARs. I'm also considering ponying up my own money and buying a DD Omega rail for my issue M4 just to get rid of that irritating wiggle.
  5. surf


    Jul 7, 2010
    The standard non-free float type are generally direct replacements. Free floats are not all the same. Some have proprietary barrel nuts, some are one or two piece. A free float can improve accuracy as you remove pressure off the barrel. For some this may not be as great of a concern in a battle type rifle.

    It would help when asking questions to include pictures or links to your rifle and / or parts that you wish to use.

    Why do you feel you need a piston kit?
  6. Like I mentioned above, the Troy MRF-DI is a a very solid drop-in rail. I have used them on 2 rifles and there was absolutely zero movement whatsoever on either of them.
    Last edited: Jan 16, 2011
  7. ScrappyDoo

    ScrappyDoo Tacticool brah!

    Jan 16, 2010
    Captain and Ezterra thank you very very much, that was very helpful and much appreciated.

    So I am thinking I'm looking at the Daniel Defense Omega Rail 7.0

    That's what we're talking about right? And this is good because it's a Free Float rail, but it's user-installed so I can do it myself ? (now help me here, it says User Installed, is this user-who-is-not-an-infantryman or Marine rifleman, so I could do it, or is it a User who knows more than a normal person?) ... Because if this is good to go for someone like me, I'm going to go ahead and just get it... I think it's just what I'm looking for (and again, I am not a rifleman running competitions or serving in the Mid east, I have a Bushmaster for shooting at the range, for having lots of fun, and practicing to hopefully develop my skills a little and be prepared for problems, be it SHTF, hajjis invading my neighborhood and or our neighborhoods, Zombies, or home defense etc. So I don't need a Colt with total LaRue Tactical and ACOGs etc. but I do like fairly nice stuff and want to do it somewhat right.. for $240 I can do that, no problem. Thanks again guys you were most helpful and appreciate thart.
  8. AK_Stick

    AK_Stick AAAMAD

    Jan 20, 2004
    Alaska, again (for now)
    Daniel Defense has a drop in free float handguard. It would be my reccomendation to someone who didn't want/have the tools to install a typical FF one.

    I run a Larue, on my Bushhampster. You have to punch out the pins holding the old gas block on, remove it, and the gas tube, then install the new ones after you've installed the rails.
  9. Yup, that's the one, a free float rail that drops in. It is very easy to install, all you need is a screwdriver. The only thing I recommend that's not in the instructions is to apply a small drop of BLUE loctite on each of the 8 screws, it probably isn't needed but certainly won't hurt. You will not be disappointed with this rail, I promise you.

    Here is a tutorial with pics on the DD Omega install:
    Last edited: Jan 17, 2011