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GEN 2 Silent Captured Spring (patented) for AR-15-type rifles


 Product Description

The JP Silent Captured Spring is a drop-in module replacement for the traditional buffer plunger and buffer spring components of the AR-15 and AR-10 platforms. By all but eliminating the raspy scraping of the buffer spring against the interior of the extension tube, the JPSCS yields a virtually silent cycling action with a dramatic reduction in friction and vibration during live fire. To achieve the utmost from the JPSCS, we recommend lightly oiling the spring and guide rod of the unit periodically. If the unit becomes fouled, clean with hot, soapy water, blow dry with compressed air and apply light oil (rather than grease) to the spring and guide rod.

While the JPSCS has been tested in numerous rifles without malfunction, this is no guarantee of function in all rifles. As with any gas gun component, there are simply too many possible rifle configurations, barrel lengths and calibers available within both the AR-15 and AR-10 platforms to test and verify universal function of the JPSCS system. See reverse for known compatibility issues, and if the unit does not function in your rifle, please contact JP via phone or email to arrange a return of the JPSCS to the original point of sale.

During regular rifle maintenance, check the tightness of the hex head screws at the ends of the JPSCS. If they are loose, remove them and clean the threads. The rear screw should be installed with a permanent thread locker such as Loctite® 263. The front flange screw is better secured with a semi- permanent thread locker like Loctite® 243.

If you find that you are experiencing bolt bounce issues, we recommend upgrading one or all of the steel masses to tungsten. The SCS comes in two standard configurations: one with all steel masses that equates to a standard carbine buffer and another with two tungsten masses and one steel that is equivalent to an H2 carbine buffer. You can also purchase individual tungsten masses to achieve any level of buffering mass you require.




Remove the existing buffer and spring by slightly compressing the buffer and then the buffer retainer plunger with a small punch. Release the buffer slowly, removing it and the buffer spring from the extension tube.

If you are using a rifle-length stock and extension tube, insert the white spacer into the extension tube. This spacer is not needed for carbine stocks/tubes.




While the JPSCS will function with or without them, you can remove the buffer retainer plunger and spring at this point. With these components removed, installation and removal of the JPSCS is much easier, though be aware the traditional buffer and spring components will be cumbersome to use without the retainer and plunger.

To remove the retainer plunger and spring, you’ll first need to remove the stock and buffer tube from the receiver to gain access, after which you can reinstall the extension tube and stock taking care not to lose or damage the rear takedown pin detent and spring.

  1. Install the JP Silent
    Captured Spring
    into the buffer tube.
    You may have to
    depress the hammer
    to the cocked position
    or a little further
    to allow enough
    clearance around the
    trigger components. Likewise, on certain two-stage triggers, you will have to hold the hammer in the half-cocked position to achieve sufficient clearance.

  2. Reassemble the upper and lower assemblies with the front pivot pin and slowly lower the upper into position. Watch carefully as the receivers are closed to verify that the SCS buffer head contacts the bolt carrier. If you are not certain if there is a gap, finish reassembling the rifle and then shake it back and forth gently listening for the sound of the SCS sliding back and forth in the buffer tube. The unit should not be moving freely.

    The precise length of the SCS was chosen to accommodate most rifles, but if you detect a gap between the bolt carrier and SCS, this is due to slight variations in the manufacturing tolerances of the buffer tube, bolt carrier and receivers. To shim this gap, the best solution we’ve found is to simply place a quarter in the buffer tube before installing the SCS. It will not be necessary to use more than one, and you should not use extra shimming to “preload” the SCS. We offer alternate rate springs for this purpose.

    If you find the SCS protruding too far out of the buffer tube into the receiver and the rifle is having trouble locking back, you can shorten the plastic spacer as needed, but take care not to remove too much material. The bolt carrier and SCS should be slightly tensioned against each other in final assembly and should not move freely in the rifle. 


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