Any JRC Mechanics? Buffer Tube JRC 9 mm issue

M

Markit

CGN Regular
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Disassembled the JRC 9 mm after 600 or so rounds.

Buffer tube had been cross threaded when installed. Was a ##### to remove once castle nut loosened and backing / lock plate push rearward.

Rear of receiver is fine but buffer tube threads are toast.

Not impressed at all, but whatever, I can deal with it if I get some guidance as set out below.

Read on JRC website u need a buffer tube with 8 1/2” internal length.

What is weird is that I inspected / measured the buffer tube on the JRC and internal was 7 1/4”.

BUT, strangely, inside the buffer tube appears to be what looks like a frost plug pressed in at the rear. It wont come out unless I force it from the rear (tube has a small hole in the rear and I can drill it out and use a punch to drive it forward as buffer tube is completely toast.

I have assembled a lot of AR’s in my time and I have never seen this frost plug looking thing in a buffer tube before.

So the question is, has anyone installed a 7 1/4” or 7 1/2” (what I have on hand) deep buffer tube onto a 9mm JRC without issues?

Do I need to install that weird frost plug thing or can I slip a few quarters in there?

Any advice is muchly appreciated as I don’t want the bolt / cocking lever slamming rearward into the receiver and causing damage.

Many thanks,

Markit.
 
I just checked my JRC and I've only got 5 7/8''. Its the factory buffer tube and I've had hundreds of rounds through this thing with no problems including some 64rd Canadian and British surplus. I wonder if you can't get away with putting some rubber disks in your tube. If there is contact it will be like a bump pad.
 
There's a black rubber plug and a white nylon disc that are installed before the spring in the buffer tube, my guess is that's what you're seeing. You need to reuse those when you replace the buffer tube.

Not sure if they changed the newest JRCs, but mine came from the factory with a commercial spec buffer tube. Just a FYI for when you replace it. If you're not in love with your stock, and were thinking of upgrading, now is a good time to go mil-spec.
 
Unholysavage said:
There's a black rubber plug and a white nylon disc that are installed before the spring in the buffer tube, my guess is that's what you're seeing. You need to reuse those when you replace the buffer tube.

Not sure if they changed the newest JRCs, but mine came from the factory with a commercial spec buffer tube. Just a FYI for when you replace it. If you're not in love with your stock, and were thinking of upgrading, now is a good time to go mil-spec.
Click to expand...

Thanks for this. Drilled the rear and then pushed out the rubber plug. No white nylon disc but a rubber rod 1 1/4” long.
 
I use compressed air to remove the rubber bolt buffer .
You can use any AR buffer tube as long as it is the same internal length or longer .
I use fix stock tubes on mine and make a spacer under the rubber buffer so it is the same internal length
BWid8bdl.jpg
 
The bolts has a shorter throw...hence the shorter tube, I install a standard AR buffer tube on my JR once...too long , sheered off the bolt handle, called JR, and they sent me two free of charge!...it was my fault, and they still sent parts for free! Great company to do business with! That alone is worth every penny I spent on my JR, and the reason, I'd buy another one over , just about any other one.
 
Thanks all for your assistance with this.

Interesting conclusion to this buffer tube issue.

Thanks to a very knowledgable and helpful CGN’er found out the 9mm JRC i purchased came not only with a cross threaded buffer tube but also with a 40 cal buffer.

New 9 mm buffer ordered from JRC this am and yesterday I received the new buffer tube I ordered a few weeks back from JRC.

FYI the vendor I purchased this from (who I will not name) was unwilling to assist or deal with this.

Totally unimpressed - This will be up for sale on equipment exchange or consignment at the LGS once the correct buffer is installed.
 
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