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AR-15 question

Discussion in 'Shooting Related Threads' started by Single Shooter, Jan 30, 2010.

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  1. Single Shooter

    Single Shooter TS Member

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    Hello everyone. i have bought an AR-15 rifle a few months ago and i am wondering what is a gas block? Does every AR have one? Does it matter what your front sight is. Please describe a gas block for me.


    ZACH
     
  2. K80Dude

    K80Dude Member

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    Yes every AR has them in some form. Any DI (gas operated, standard AR system) will have one in a standard format. The gas block is where the gas is released from the barrel and enters the gas tube that runs back to the bolt and causes the bolt to cycle. AR's that are piston driven have a "gas block" but are a little different. I am not sure what you mean about the front sight....The milspec front sight will have an "F" stamped on the side, however there are rail mounted front sights as well.
     
  3. Leo

    Leo Well-Known Member

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    On a standard A2 infantry style configuration, The gas block is part of the front sight. You can see the gas tube exiting from the rear of the front sight slightly over the barrel and leading back into the receiver. On configurations where the military syle sight is not used, there is a block that attaches around the barrel that also sends the gas into the same type of tube. Good Luck
     
  4. Brian in Oregon

    Brian in Oregon Well-Known Member

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    Not every AR has a gas block. The exceptions are:

    AR15s that are chambered for some pistol cartridges. These are set up as blowback actions. Often the upper receiver does not even have a hole for the gas tube to pass through, and the "gas block" is purely a front sight or front sight base, if it even has those.

    AR15s that are set up as straight pull manually operated bolt actions to get around so-called assault weapon bans. Can you say, "Thank-you Commiefornia"?

    AR15s set up with single shot uppers for large cartridges, such as the .50 BMG.
     
  5. oz

    oz Active Member

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    for a lot of answers go to AR15.com oz
     
  6. Single Shooter

    Single Shooter TS Member

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    ill explain what i meen by the front sight.

    i have a standard A style pinned front sight and i wanted to remove that sight and put a flip up sight in front but if i do that will i need to purchase a seperate gas block to place where the original sight was?
     
  7. V10

    V10 Well-Known Member

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    Yes. See video above. It might help you understand.
     
  8. capvan

    capvan Active Member

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    Short answer...yes, you will have to install a seperate gas block if you take off that "A" style front sight. Can be done, but it's not easy. It IS easy to mess up, however!
     
  9. Brian in Oregon

    Brian in Oregon Well-Known Member

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    If you want to switch front sights, there are some options.

    First, it is a royal PITA to drive the pins out and install a new front sight or gas block that also uses pins. The sights are drilled and reamed while on the barrel. Now you're trying to replicate that alignment with a new sight. Most people are not set up to do this correctly. A few gunsmiths will, but most of them have made special alignment jigs to hold the sight and barrel in properly alignment. My recommendation is that you do not try this.

    Second, there are sights and gas blocks that are essentially clamp on. They use various types of set screws to hold these parts to the barrel. These are much easier to work with, but lack the variety of styles.

    Third, there is an alternative that would require your sight tower be cut off your gas block. You'd have to refinish the bare metal after doing this, but there are high temp epoxy style paints that work well. Bushmaster makes a special folding front sight that clamps onto their V-Max and hunting gas blocks, which are nothing more than a regular front sight assembly cut down into a gas block.

    [​IMG]<br>
    For example, here is a Bushmaster Optics Ready Carbine. It has the cut down front sight tower.

    [​IMG]<br>
    This is the Bushmaster clamp on folding front sight for their cut down sight towers.<br>
    It's about halfway down on this page<br>

    I'm considering setting up back-up iron sights on my Remington R15 carbine, which has the same style cut down gas block (because it's made by Bushmaster), along with a detachable rear sight (can't use a folding rear sight because there's no room due to the scope I'm using). But this would give me an alternative if the scope should go south on a hunt.
     
  10. AAtrap

    AAtrap Well-Known Member

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    I just removed the "A" style front sight from my DPMS AP4 carbine and replaced it with a clamp-on gas block with top rail so that I can put on a lower profile sight or laser if I wish. As mentioned above, " a PITA". First of all, removing the pins was not easy and then getting the holes to line up so that the gun would cycle was a trial and error thing. Everything ok now, but I'd think twice before doing it again in the near future.

    Good luck
    Steve
     
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