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Thread: Jard J180 Builds

  1. #1
    Member The Crover's Avatar
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    Jard J180 Builds

    Just started building my Jard J180 receiver and found a few issues already.



    There is no way to install an A1/A2 stock on this receiver, as the geometry of the receiver differs from an AR-15's lower. The dimple the stock would fit into on an AR lower to prevent rotation does not exist in the J180 receiver or trigger pack.

    This will also impede instalation of sling loop plates commonly used with carbine buffer tubes. It seems the only stock options that will work with the J180 are collapsible stocks.

    The barrel nut instalation is also difficult. Geissele reaction rods do not fit into the receiver as the stock tube channel is lower on the receiver than on the AR-15. There is about 1 cm difference between the center of the stock axis and the barrel axis. Magpul BEV block does not fit into the receiver, so the barrel extension locking lugs cannot be engaged from the inside of the receiver.

    My first attempt to tighten the barrel nut of a BCM MCMR handguard involved clamping the barrel on a vice with wood blocks to prevent marring the finish. I was unable to tighten the nut using my torque wrench to BCM spec of 40 ft/lb without the barrel slipping in the wood blocks. The only way I managed to secure the upper was using some thick fabric wrapped around the upper itself to prevent marring, and then clamping the upper lightly near the barrel using the vice. I was then able to tighten the barrel nut to 40 ft/lb.

    I'll continue to update this thread as I build my rifle into a working unit.

    Update one: https://www.canadiangunnutz.com/foru...1#post18395392

    Range report #1: https://www.canadiangunnutz.com/foru...1#post18398441
    Last edited by The Crover; 10-27-2021 at 11:50 AM.
    The Abomin870!

  2. #2
    Super GunNutz jiffx2781's Avatar
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    I'll just keep shooting what I have.
    "Arguing with idiots is like playing chess with a pigeon..... No matter how good you are, the bird is going to s#!t on the board and strut around like it won anyway."

  3. #3
    Member The Crover's Avatar
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    Quote Originally Posted by jiffx2781 View Post
    I'll just keep shooting what I have.
    Sounds good.
    The Abomin870!

  4. #4
    CGN Regular $kull's Avatar
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    You can use a sizeable picitinny riser on the rail and use that in a vice
    , upper upside down, to torque the barrel nut

    Don’t see the a1 or a2 stock being an issue since most would only ever want that for a rifle length gas system AND rifle buffer system to soften an ar’s recoil and enhance reliability.. both not factors for this rifle. Much better to have it fold, in my opinion, since it actually can use cheap folding Ar stock adapters meant for bolt guns and still fire folded. Others mileage may vary, if you are older than water, need to “retro” anything that takes a magazine in it, or have cheese string arms or whatever

    But good you found that out for those guys.

    I had success modding a bev block with a dremel to fit a modern sporter, will see if it fits this when it arrives and update and contribute to this thread.

  5. #5
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    Does anyone have an A2 stock, the MRA A2 end plate adapter for their Renegade/Maverick, and a Jard J180 build kit to see if the plate will work for then J180? It says it is proprietary to the MRA designs, but I wonder if it may still work on the J180.

  6. #6
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    I phoned Sylvestre, and they had run into the same issue as the Crover with another customer. The customer really loved the A2 stock, and came up with a permanent solution. The customer tightened the buffer tube to the maximum, and then used epoxy to permanently attach the A2 stock to the buffer tube.

    I passed along the suggestion of the MRA A2 end plate adapter to them, and they plan on ordering one to test with the J180. In the meantime, they will note the current A2 incompatibility on the J180 web listing when it is created.

  7. #7
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    Edit, The Crover posted updated impressions himself.
    Last edited by Ustauk; 10-25-2021 at 11:22 PM.

  8. #8
    GunNutz 257hunter's Avatar
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    I used a mdt carbine to fixed adapter to solve a similar issue installing an ar stock on my contender carbine. Might work for you.

  9. #9
    Member The Crover's Avatar
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    After some struggles finding an appropriate stock for the rifle, the J180 is put together!

    First impressions are...ok. The weakest part of the platform is the fit and finish. It is not anodized I think, it is a matte grey color and feels like parkerization but I don't think you can parkerize aluminum. There are machining marks in many places, and the trigger pack is assembled from 2 halves and bolted together. There was an abundance of packing oil on and inside the receiver, but it all wiped off easily.

    The bolt cam pin track was marred out of the box. Looks like cycling and dryfiring the receiver might have caused the cam pin to strike the track, the marks are on spots the pin might not have reached if the BCG had been in the correct position in the receiver when stopped by the barrel extension.

    Trigger is pretty decent out of the box, single stage trigger pull is on the light side with a short audible and tactile reset. It has a quirk where the trigger seems to lock up if the safety is set to "on" after the hammer is dropped but before resetting it. Only way to remediate is to remove the trigger pack off the gun and reset the hammer manually with the safety off.

    Since the recoil rods and spring are higher on the receiver, the height of the receiver is higher than the height a standard AR receiver; this causes the receiver rail to be around 3-4 mm higher than a standard AR handguard rail I would guess. This in turn causes a very pronounced issue with AR-height optics, necessitating a higher comb on the stock to properly look through optics. Using a Magpul MOE stock and 0.5" cheek riser the AimPoint PRO can be used normally.

    Last but not least is the issue of stock options. As I've previously indicated, A1/A2 stocks will not work on this receiver set. However, I found the Magpul fixed carbine stock will work as it interfaces with the geometry of a carbine buffer tube to prevent rotation.

    Range report soon!
    The Abomin870!

  10. #10
    Member The Crover's Avatar
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    Quote Originally Posted by Ustauk View Post
    From Over on Reddit, the Crover posted:
    Getting a little ahead of yourself! I updated the post on Reddit with more info so yours is out of date.

    I posted the complete comment here so not sure if you want to edit this one or delete the comment.
    Last edited by The Crover; 10-25-2021 at 10:53 PM.
    The Abomin870!

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