JR Carbine Discussion and Parts Swap


When buying a new firearm,  swapping parts is usually not the first thought that comes to mind. My thought process  usually starts with me going to the store, fondling a potential new purchase and trying to resist the initial urge to buy it.

I will then go home and try to read as many reviews as possible, paying close attention to the negative reviews as well as the positive. Negative reviews will help to point out possible mechanical issues, availability of parts / service and maybe even buyers remorse, the positive reviews will help to ensure the particular gun will be a good purchase. If I’m really fortunate, someone at my range will be using the particular gun that I’m interested in and are generous enough to let me bang off a few rounds. An example of that being the Benelli M4 shotgun that I purchased,  but that’s a post for a later date.

I bought my JR Carbine, during a Western Canada road trip with my brothers in the summer of 2012,  I was looking to bring back a firearm as a souvenir from my journey out west, and I was looking to buy a non-restricted and now non-registered rifle black rifle.  While stopping to visit family in Moose Jaw, my cousin and I went to Avolea to visit Pairie Gun Traders (http://www.prairieguntraders.ca/), a fantastic little store, with great service and  selection of firearms for sale.

While at Prairie Gun Trader, I fondled several firearms, and I was torn between the Keltec SU-16 and the JR Carbine. I didn’t quite like the feel of the Keltec, the polymer receiver was a bit of a turn off for me. I had read negative reviews where the receiver was cracking, and I didn’t want to take the chance.  For the JR Carbine, the only negative reviews that I could find, were cycling issues with the 45 ACP version of the rifle.  When I handled my soon to be purchased rifle, the fit, the feel, the finish was great, and the rifle just felt right against my shoulder.

The four  biggest selling points for the JR Carbine:

  • Firstly, a centre rifle rifle in (relatively affordable) 9×19 mm ammo
  • Secondly, it used widely available and reasonably priced Glock 17 magazines
  • Thirdly, the rifle shares many parts as an AR-15, such as the stock, grip, trigger, safety selector, making repairs and possible upgrades in the future easy
  • But the biggest of all,  the rifle is non-restricted!

When I initially bought my JR Carbine, I was happy with just the factory layout and was running the rifle with a SPARC vortex red dot. However, in the fall of 2013 after seeing other JR Carbine owners upgrades on CGN,  I decided it was time to swap parts on mine.

List of parts added that I purchased for my upgrades:

  • Magpul M.O.E Stock – milspec
  • Rainer Arms buffer tube
  • Magpul M.O.E angled foregrip
  • Magpul M.O.E grip
  • Vortex ADR Cantilever QR Ring Mount 3″ Offset W/ Quick-Release
  • Vortex Viper PST 1-4 MOA illuminated reticule

JR Carbine – Tear down and reassembly with new parts video

After swapping several components, I wasn’t fond of the stock 4 rail hand guard, it took some time, but Canadian Tactical Cowboy supplies (CTCsupplies.ca) had the Yankee Hill Machine Diamond forearm rifle length in stock and I snatched one up and performed the swap.

JR Carbine – 4 rail handguard swap video

The biggest hurdle to the swap, was the anti-rotational screws not lining up with barrel nut, this problem was solved, by using a VW transmission drain plug washer as a shim. I sourced the part from a local VW dealership.

JR Carbine – Range video

After swapping out all the components, I’m happy with the way the rifle looks, it definitely catches the eye at the range, however, the biggest draw back is now the additional weight. Sadly, I don’t have a before or after comparison for the weight, but the rifle has gained a few pounds.

  • kkor

    I just have a question regarding the Yankee Hill Machine forearm swap. You managed to get the rifle length but would it work with a different length forearm?

  • No real difference. There isn’t a gas system to cover, so any length forearm will work. Longer forearms allow for more room to rest on a barricade, longer sling mounts, etc. You may still have some of the difficulties Matt and I had with fitting the forearm due to the different mounting depth on the JR.

  • Matt Capranos

    I choose the rifle length as it hid more of the barrel. It’s one of the things I didn’t like about the JR carbine, a tiny hand guard / four rail and such a long barrel.

    Any free floating hand guard should work for the JR Carbine.
    As Adriel said, some fitting might be required to line up the hand guard.

    I had to rely on a VW transmission drain plug washer to shim the barrel nut so that the hand guard would line up for the anti-rotational screws.

  • mark

    I have a question. Do you think a Dolos AR15 Removable Barrel System would work on the new JR carbine Take down model?

  • David Kiddell

    When you mention “VW transmission drain plug washer” do you mean part no 09D-321-181B?

  • fightbackandwin2

    What is the length of the quad rail? Can’t locate that info, even on JRC website. Thanks.

  • TGO

    It is a little longer than 12″….. http://www.primaryarms.com/yhm-9635-dx/p/yhm-9635-dx/

  • fightbackandwin2

    Sorry, wasn’t very clear. I meant the factory one, but I found it. I’m in Maine, we’re almost neighbors, haha. Thanks.

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