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Lightweight boltcarrier

Discussion in 'Black Rifle Forum' started by ottomatic, Jan 3, 2011.

  1. ottomatic

    ottomatic

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    I just finished building a lightweight AR at 5 3/4 lbs w/empty 20 rd mag, Burris Fastfire2, and a 90 lumen light (not the brightest, but maybe the lightest REAL light). A buddy and I were just looking at it and trying to figure out if one can lower the weight any more without going to exotic materials. He suggested a lightweight boltcarrier. I have access to a machinist who coud probably get some weight off it for very little money.
    The question is: would a lighter boltcarrier require a lighter buffer or a heavier one? My guess would be a lighter one.

    Who has a good guess or (preferably) a physics/engineering background to help out?
     
  2. USMCsilver

    USMCsilver Boat Life ©

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    IMHO, you'd need a lighter buffer because the bolt carrier would not have the same energy to travel to the rear.

    *deleted partial thread*
     
    Last edited: Jan 4, 2011

  3. boomhower

    boomhower

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    You can buy them premade. They are designed for the competition crowd. Click Me
     
  4. faawrenchbndr

    faawrenchbndr DirtyThirty fan CLM

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    Boomhower nailed it,

    Give JP Enterprises a call, explain your needs and get proven results. I would suggest get their bolt and buffer.
     
  5. ottomatic

    ottomatic

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    I appreciate the replies. I looked at the link and that appears to be a good bolt carrier, but I don't want to lose the forward assist function. This whole rifle has been an interesting project. The optics are a must as she is cross eye-dominant, but has other problems trying to shoot left handed.
    I actually have the results I wanted, at this point additional weight loss is more of a game than anything else. The only limiting factors are I don't want to use exotic materials such as carbon fiber and titanium, and I want the cost to stay reasonable. So far I'm in the mid $800 range including the optics and light.
     
  6. Halojumper

    Halojumper

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    I think it would be just the opposite, that you'd need the same or heavier buffer. Look at it this way. Since no mention was made of changing the gas system, I am assuming that it is the same. If it is the same and the bolt it lighter, it will be moving rearward faster. It's a lot like when you lighten a slide or use more powerful ammo in a handgun. In those cases, people us heavier springs, not lighter. Remember, the mass of the bolt/slide contributes to the inertia that controls the movement.
     
  7. Hoser

    Hoser Ninja

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    Wrong concerning the lightened slides part.

    If you run a lighter bolt carrier you can use a lighter not a heavier buffer. If you lighten the carrier and use a heavier buffer you didnt gain a thing.

    I use a JP light stainless carrier and a Firebird/PMT Ti carrier in my competition rilfes. Less moving mass means less sight movement on recoil.
     
  8. faawrenchbndr

    faawrenchbndr DirtyThirty fan CLM

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    Correct,......lighter buffer to control the lighter carrier......less moving mass requires less buffing.

    Make sense? :dunno: :rofl:
     
  9. Bushflyr

    Bushflyr ʇno uıƃuɐɥ ʇsnɾ Millennium Member

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    If you run a light carrier and buffer you really ought to use an adjustable gas block too. With the standard unit you'll be overgassed.
     
  10. Hoser

    Hoser Ninja

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    Every adjustable gas block I have had (JP and PRI) ended up being full open. So I went with a normal gas block. One less thing to break.