DK Firearms

Converting to 7.62x39?

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  • Murfpcola

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    I have been thinking about swapping out a barrel on an AR I have. I had been planning on swapping my 14.7" rifle length heavy barrel for a lighter profile 18" barrel but now I have thought about swapping over to 7.62. To make sure I am thinking correctly, what all will I need for the swap? I am thinking just a bolt, not complete BCG, barrel, flash hider, maybe a gas block and a magazine. Does that sound correct? Should the barrel nut interchange? I would be using the PSA free float handguard that is on the gun already.
     

    kendive

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    I am not 100 % but the 5.45 Bolt won't work. The bolt face opening on the 5.45 is slightly larger than the 5.56 but smaller than the 7.62x39.

    Might have to get a complete BCG?
     

    FNHman

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    buy a 7.62x39 bolt, barrel, mag, and flash. Your barrel nut will be the same. You will use the same gas block if you already have a .750 but your gas tube length depends on the type of barrel you get as some have pistol length holes but that would be more common for the shorter barrels and subsonic 14.5" and 16"

    here is a 7.62 18" mid length barrel
    https://www.kakindustry.com/ar-15-p...ch/contract-76239-18-inch-mid-melonite-barrel
     
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    SAWMAN

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    Like FNH sez but would like to add - - -> Consider buying a complete upper. Consider buying a .308" bbl vs the normal .310/.311" bore IF you will be reloading for this gun. If spam can ammo will be used the standard bore size is good. You CAN use the .308" bullets in the larger bore guns,however accuracy will suffer. I do not know what accuracy you are expecting but I have seen some .308" bore guns shoot pretty darn good.
    If you do end up with a .310/.311 bore gun and will reload for it,take a look at the bullets designed for the 303British also.
    Please post what you end up with as I' m sure it will help others. --- SAWMAN
     

    Murfpcola

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    I wound up ordering a complete upper including BCG and CH from Sander's Armory. I will update after shooting it.
     
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    Murfpcola

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    I have read about the enhanced firing pin and will see how mine does as is hopefully Wednesday. Something else I will probably need soon is a heavier buffer. The barrel is 16" carbine length gas. Nate thought that this setup will probably need either an H2 or H3. Any input on that? Anybody got any buffers laying around I could try and buy if they work? I would like to get the weight right the first time but I know that does not always happen.
     

    FrankT

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    My regular firing pin would not fire the steel ammo and trying it will damage it. Mine was a Carbine from Hardened Arms $300 and worked with the standard spring and buffer, all I added was a bolt and enhanced FP, ran 100%
     

    Murfpcola

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    Y'all lost me

    The enhanced firing pin is machined so it protrudes a few thousandths more than a standard firing pin. This helps with firing the hard primers that the steel case 7.62 is known for. As far as buffers go you want the heaviest buffer you can get and still have your rifle cycle the ammo and lock open on the last round. the 7.62 supposedly has substantially more recoil than the 223. At least this is what I saw on the internet:)
     

    Django

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    Please keep us posted on the upper. Im cosidering getter another one. I went to the website and saw that they had a side charging handle upper as well. Looked pretty cool. The 7.62x39 upper I had cycled fine unit I tried a heavier buffer spring. That ended up short stroking.
     

    Murfpcola

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    I shot this gun some more yesterday. I installed an enhanced firing pin from Red X Arms and a Wollf extra power hammer spring and had zero light strikes. I ran the ten rounds through that already had light strikes and they all fired too. I now have 130 rounds of Tulla, Wolf and Monarch steel case ammo through it and so far ZERO failure to feed or eject. Again I am using C P Defense 10 and 30 round mags. I am no precision shooter but I was propping up on the corner of my truck bed with a block of wood and was easily hitting a paper plate at 150 yards with my steel case ammo. Very happy so far. With the kick a quick follow up shot is much harder than with .223 though.

    Edit for my own records. I am at 280 rounds now. I also have swapped back to the standard hammer spring to lighten up trigger pull. So far no light primer strikes with just the Red X enhanced firing pin.

    Edit nov 2 2019. After diagnosing light strikes it is back running good after replacing firing pin. Round count is now 350

    Edit nov 9. I shot another 84 rounds. Light primer strikes started again. Also buffer came apart. Round count now 434

    Nov 29. Round count now 519. Shot 85 rounds today through 3 lowers and had a few light strikes but only from the Rise Armament drop in trigger. I am leaning towards maybe it has gotten a little weaker/slower over time causing the light strikes.
     
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    Murfpcola

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    Went shooting today and shot the 7.62 some more. Put 60 rounds through some new ASC mags that I got and still have had ZERO feeding or extracting issues with the upper. I still love it. Shooting clay pigeons at 100 yards with steel cased wolf ammo is no problem and I am not a great shooter.
     
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