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home Forums – The GUN Forum Firearms Rifles AR15 Question: Why can we put a front BUIS on a free-float rail, but not a red dot? Wouldn’t the hand guard affect the accuracy of your irons?

  • Question: Why can we put a front BUIS on a free-float rail, but not a red dot? Wouldn’t the hand guard affect the accuracy of your irons?

    Posted by gulagfengshui on August 6, 2022 at 10:42 am

    Question: Why can we put a front BUIS on a free-float rail, but not a red dot? Wouldn’t the hand guard affect the accuracy of your irons?

    gulagfengshui replied 1 week, 5 days ago 2 Members · 15 Replies
  • 15 Replies
  • 3TOnTheTrail

    Guest
    August 6, 2022 at 10:42 am

    I believe it falls under necessary evil versus something that can be mitigated.

  • Mother-Adversary

    Guest
    August 6, 2022 at 10:42 am

    Yes. But it’s super backup. So by the time you get to use it you’ve already bled out. And your last thoughts are about how r/ar15 mocked you for bridging your optic.

  • AnalogCyborg

    Guest
    August 6, 2022 at 10:42 am

    Welp, I’m officially moving my front sight to the end of my upper receiver instead of the end of my hand guard.

    You ain’t gonna drag *me*, reddit.

  • RolandDelacroix

    Guest
    August 6, 2022 at 10:42 am

    Correct. Especially on the current popular skinny rails that flex alot, and even more if you are properly using a sling.

    If you are gonna use irons for more than a backup, you want a railed gas block or a very sturdy rail. Maybe something monolithic or like the M4e1 Enhanced properly torqued.

  • sambone4

    Guest
    August 6, 2022 at 10:42 am

    For the same reason it’s okay to mount an IR aiming laser on the free float rail, it’s not meant for accurate shooting at extended ranges, the realistic use case for both lasers and BUIS is maybe like 0-100 meters. Typically anyone who’s serious about running an IR laser is also running a very rigid rail so that laser will hold zero. That said you wouldn’t want to run your primary optic on a rail like that, it can still be bent or damaged or even affected by barrel harmonics via the barrel nut since “free floated” ARs aren’t really actually free floated if you want to get technical about it.

  • Cadi009

    Guest
    August 6, 2022 at 10:42 am

    BUIS are literally Back-Up Iron Sights. Key words “back-up”. If you have to use them at all it presumably means shit has already gone wrong with your optic and you still need a method of aiming no matter how crude.

    If iron sights are your primary sighting system, then you should have a pinned front sight block and a fixed rear sight full stop.

  • CarnitasTac0s

    Guest
    August 6, 2022 at 10:42 am

    Iron sights are not precise like an optical sight. Nowadays iron sights are mostly for backup reasons anyway so it isn’t as big of a deal.

  • Sea-Example-8767

    Guest
    August 6, 2022 at 10:42 am

    People who say you can’t use buis on a free float rail are stupid

  • ProximusAlpha

    Guest
    August 6, 2022 at 10:42 am

    Vibration could muck up your optic. That’s not to say that a flip-up BUIS couldn’t get damaged, but it probably be due to hitting something while they are up. Accuracy-wise, the flex of the handguard (to say nothing of rotation) makes a rail mounted front sight a less optimal alternative than a fixed steel FSB when it comes to POA vs. POI. That said, if you’re at/within 100 to 150 yards, it probably won’t prevent you from hitting a 12 inch target unless your handguard twists or you really flex it.

  • Guitarist762

    Guest
    August 6, 2022 at 10:42 am

    Not as precise as an optic to begin with, plus most people can’t shoot well enough with irons to really tell a difference.

    The only true way to test it by having one with BUIS on free float rail vs rifle that has say a fixed front sight post. But then you run into stuff like, how different rifles shoot different ammo better than others, barrel harmonics, sight radius, shooter, the general precision of the rifle in the first place and the such. Too many variables to really tell, plus while I feel very good with irons seeing I generally shoot them better than most red dots I honestly wouldn’t be able to tell you that any noticeable difference wouldn’t just be me, or something else mechanical from the rifle.

  • KidQayin

    Guest
    August 6, 2022 at 10:42 am

    Different levels of precision.

  • ardesofmiche

    Guest
    August 6, 2022 at 10:42 am

    It does affect accuracy of irons, but to a differing degree.

  • TOClife

    Guest
    August 6, 2022 at 10:42 am

    If it’s a solid mounting system, I honestly do not see a problem. Not all rails can have a solid system of mounting to the upper. Geissele rails with the anti cant features and the monolith uppers, etc

  • SilverHerfer

    Guest
    August 6, 2022 at 10:42 am

    It’s not so much why can you, it’s you have to. First, where else can you put a backup sight? Second, it’s got to go out there to get a good sight radius.

  • Key_Football_8548

    Guest
    August 6, 2022 at 10:42 am

    Iron sights for life

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