Gunsmithing Gunsmith recommendation to chamber AR 15 to 223 AI

krummarine

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Does anyone know of a good 'smith that could rechamber a Rock River varmint upper to 223 Ackley Improved? Is this even possible?

Joe
 

KUSA

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Re: Gunsmith recommendation to chamber AR 15 to 223 AI

What would be the point in doing that? Unless you want to single feed it you can't load the rounds long to take advantage of heavy bullets.
 

Mgordon

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Re: Gunsmith recommendation to chamber AR 15 to 223 AI

I have a new .223 AI reamer I was just itching to get in a tube. After looking over the link above, I still dont know if we can run this reamer into a pre chambered barrel and have tight enough headspace because if we take a few thousands off of the barrel shoulder then our barrel extension wont line up with the gas port.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">"The chamber can be reamed out so that the new chamber just barely cleans up the corner between the shoulder and neck, but this will not produce a crush fit which is necessary for fireforming factory ammunition. So the headspace has to be about .004 inch under minimum go gauge... it is almost always necessary to turn the barrel in a little bit in order to minimize headspace."</div></div>

I can do the work no problem assuming that the statement above means we will not have to turn the barrel shoulder back.

Mark
 

krummarine

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Re: Gunsmith recommendation to chamber AR 15 to 223 AI

thanks, US. PM me with a quote for the work if you would.
 

Red_SC

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Re: Gunsmith recommendation to chamber AR 15 to 223 AI

Could you just set the barrel back one thread, Mark?
 

toygunner

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    Re: Gunsmith recommendation to chamber AR 15 to 223 AI

    I have made three 223 AI barrels for AR 15's. They work great. The shoulder does not affect feeding at all. I can push a 40 gr. vmax at 3900 fps. The heavy bullets (69) shoot good as well. I'm not sure on the velocity increase I would need to check with the friend I built it for, but he swears by it for coyotes.

    As for re-chambering a factory barrel, it can be done, but I dont recommend it. The extension needs to be removed, which in my case required heat. Then you must remove one thread from the barrel and re-align the extension with the existing gas port. Followed by chambering and setting the gap between the bolt and breach face.

    Just using a 223 AI reamer in an existing barrel will not work.
     

    Mgordon

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    Re: Gunsmith recommendation to chamber AR 15 to 223 AI

    <div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Red_SC</div><div class="ubbcode-body">Could you just set the barrel back one thread, Mark? </div></div>

    Toygunner explained it really well.

    The biggest problem is that the gas port is almost always drilled after the headspace is set and the barrel extension is torqued on (110'ish foot lbs). Once the barrel extension is set the barrel is moved from the lathe to the mill where its held properly and indicated in to the bore. Once that is done the and the measurements have been applied the drilling starts. The gas port is now directly related to the barrel extension. You do not want to change that relationship.

    Mark
     

    Red_SC

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    Re: Gunsmith recommendation to chamber AR 15 to 223 AI

    Yeah, what he said is what I though you'd need to do. If it was set back exactly one thread, the gas port would still line up but you'd get the crush fit on the shoulder.
     

    ohnomrbillk

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    Re: Gunsmith recommendation to chamber AR 15 to 223 AI

    <div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: toygunner</div><div class="ubbcode-body">I have made three 223 AI barrels for AR 15's. They work great. The shoulder does not affect feeding at all. I can push a 40 gr. vmax at 3900 fps. The heavy bullets (69) shoot good as well. I'm not sure on the velocity increase I would need to check with the friend I built it for, but he swears by it for coyotes.. </div></div>

    Tag
     

    Clark

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    Re: Gunsmith recommendation to chamber AR 15 to 223 AI

    223 Ackley at 55kpsi will push a 40 gr bullet 50 fps faster than 223 at 55kpsi.
    223 Rem at 75kpsi will push a 40 gr 300 fps faster than 223 Rem at 55kpsi.
    223 Ackley at 75kpsi will push a 40 gr 350 fps faster than 223 Rem at 55kpsi.

    Conflation occurs when the identities of two or more individuals, concepts, or places, sharing some characteristics of one another, become confused until there seems to be only a single identity — the differences appear to become lost.

    Case capacity increase from Ackley improving a chamber would be an independent variable.
    Velocity would be a dependent variable.
    Peak pressure would be another independent variable.
    If we measure the effect of case capacity increase on velocity, but do not control [have unknown change in] peak pressure, then we have an out of control variable.

    Out of control variables have been associated with bad science, cheating, and having a screw loose.
     
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    500grains

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    Re: Gunsmith recommendation to chamber AR 15 to 223 AI

    50 fps is not worth the hassle of forming cases.
     

    Hunt

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    Re: Gunsmith recommendation to chamber AR 15 to 223 AI

    No, but not having to trim cases is.

    <div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 500grains</div><div class="ubbcode-body">50 fps is not worth the hassle of forming cases. </div></div>
     

    ohnomrbillk

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    Re: Gunsmith recommendation to chamber AR 15 to 223 AI

    I agree on the case trimming

    <div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: inode</div><div class="ubbcode-body">No, but not having to trim cases is.

    <div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 500grains</div><div class="ubbcode-body">50 fps is not worth the hassle of forming cases. </div></div> </div></div>