Beginning in 2020, JRC introduced a new, updated design for the rubber spacer/bumper located in the buffer tube. This takes the place of the bumper and plastic spacer previously used. This new updated design is a press fit in the tube to help eliminate the accidental removal. Typically this would occur during disassembly of the buttstock for cleaning. This can lead to charge handle damage from overtravel if the spacing is not properly maintained.
As an aside, this probably results in half of the repair requests we were seeing. With the introduction of this change, we have seen a reduction in new production guns needing repair.
One thing to note regarding rifles…if you are changing out buttstocks….do NOT change buffer tubes! The current production since late 2019 have been using Mil-Spec tubes meaning any mil-spec sized plastic will fit on our tube. Just change the plastic buttstock, not the whole buttstock/buffer tube assembly. We need the extra length our tube provides for the longer than std. AR buffer we use. Do NOT switch to a standard AR tube as they are shorter and will not provide proper spacing required for the system to work reliably.
Please see the online manual for further discussion of the spacing required for proper function.
I’ve seen the Germans on YouTube using a m16 A2 stock on the 9mm JRC, no info on how they did it, but it looks real nice. Maybe they just used an internal spacer. This would be a nice option to offer a internal spacer to run these tubes and stocks.
The A2 buffer is longer, so you can just add spacers to make up the difference and use the A2 stock instead of the collapsible M4 style.