I recently got the JP Silent Capture Spring to use in my rifle, and I’m excited about its user tunable abilities. With the option to change the buffer weight as well as the spring weight for AR-15, AR-10, or 9mm ARs, there are a lot of ways this can go down.
In my case, I’m tuning the silent capture spring for a low mass operating system in my AR-15. Whichever silent captured spring setup you have, these steps will apply.
Here’s the step by step process (with pictures) for tuning your silent captured spring to work with your firearm specifically.
I got my Silent Captured Spring from OpticsPlanet Here, I like using OpticsPlanet for their rewards program, but either way, the SCS was cheaper than buying direct from JP.
Here’s a full video where I show the tuning process step by step, with written steps and pictures below:
Compress The Silent Captured Spring
This is as simple as pulling back on the buffer weights to compress the spring.
When the spring is compressed enough, a little hole will be visible on the guide rod that you can insert a punch or hex key to hold it there.
Remove The Top Screw
With the spring and buffer held down, you can easily remove the top screw holding the buffer and spring onto the guide rod.
The gen1 SCS uses a 3mm hex wrench and the gen 2 uses a 1/8 inch hex wrench.
If the top screw was installed with thread locker, you may need to get a heat gun on it before you’ll get the thing to budge.
Remove Buffer And Spring From Guide Rod
With the top screw removed, you can now remove the punch or hex key you used to hold the buffer and spring down. Be careful to have a good grip on the buffer to prevent it from going flying.
Slowly decompress the spring and remove the buffer and spring from the guide rod. Be sure to keep it pointed away from your face in case you slip.
Change SCS Bumper
If you bought a SCS for your platform then you don’t need to perform this step. This is for switching to or from the AR-10 platform SCS setup.
The bumper on the AR-10 SCS setup will be smaller than for the others. It’s really easy to change out if you’ve been following the steps so far.
Simply slide the bumper off the guide rod. It was only held in place by spring tension, and at this step it will freely pull right out.
Replace with the bumper of your choosing and that’s all.
Change SCS Spring
With the SCS disassembled, now’s the time to change out the spring. I bought my SCS with an included spring pack. But you can always buy the springs separately after the fact if you want to change it later.
The springs are color coded on one end and that’s how you determine the correct spring to use.
From lightest to heaviest spring:
| JPSCS2-15 (AR-15) | JPSCS2-10 (AR-10) |
|---|---|
| White (Lightest) | Red (Lightest) |
| Black (Standard) | Red to Blue |
| Green | Red to Yellow (Standard) |
| Yellow | |
| Uncolored (Heaviest) |
Change SCS Buffer Weights
The buffer weights you can use with the SCS will be either stainless steel or tungsten. The tungsten weights are heavier and a matte grey color, while the steel lighter and shiny stainless.
The AR-15 and AR-10 versions will take 3 sections of buffer weights, while the 9mm gen 2 version will take 5 buffer weights. The more tungsten sections you use, the heavier the buffer will be.
For example, I am using 3 stainless steel weights (the lightest setup) to mimic a standard buffer weight. Removing 1 steel weight and replacing it with a tungsten will mimic a heavy H1 buffer. 2 tungsten weights will mimic a heavy H2 buffer and so on.
To change the buffer weights, press apart the snap ring holding the weights in place. I find it easiest to use a tiny screw driver for this part.
You can use the screw driver to pop the snap ring out of the groove it sits in the slider. Then you’re free to remove the buffer weights and replace for your setup.
Keep in mind, there’s an o-ring in between each buffer weight. Each buffer weight should have an o-ring on either side of it except the end with the snap ring. You need to reassemble it that way too.
Put the snap ring back in place to hold the buffer weights after getting the weight set right for you.
Reassemble The Silent Captured Spring
The SCS will reassemble the same way you took it apart. Set your bumper in place then place the spring you chose on the guide rod followed by the buffer.
Pull the buffer down the guide rod compressing the spring until you can place a punch in the hole on the guide rod.
Put the top screw back in using some thread locker. The kit comes with a bit of thread locker, but it’s only good for a few uses. Use loctite 243 to get the same effect.
JP suggests firing a few round before using thread locker on the top screw in case you want to adjust anything else before locking the SCS tuning in place. I did not do that since I already knew I wanted the lightest buffer and spring setup possible.
JP Silent Captured Spring Install
With the silent captured spring setup the way you like it. It’s time to install it in your weapon. This is the easiest part of the whole deal.
Remove Existing Buffer And Buffer Spring
Push down on the buffer retainer to release the buffer and buffer spring from the buffer tube.
The buffer retainer is the little detent that is under spring tension, is located in the back of the lower receiver, and holds the buffer in the buffer tube.
Remove Buffer Retainer
This step is optional. However, JP states on their site that you do not need the buffer retainer to use their silent captured spring in your firearm.
I left mine in just in case I want to switch back to a regular buffer and buffer spring setup at some point. If you ever want to return to a normal buffer setup, you’ll need to re-install that buffer retainer.
I don’t see an issue with leaving it in, and everything works fine with the buffer retainer still there.
Install Silent Captured Spring
If you left the buffer retainer in your lower receiver, you’ll need to depress it in order to install the silent captured spring. Otherwise, it will just slide into the buffer tube easily.
Note: you may need to push down on the hammer to make room for the SCS to slide more easily into the buffer tube.
The silent captured spring comes with a washer to place in the back of the buffer tube in case it doesn’t sit far enough forward. I didn’t need to use mine. Everything fit great the way it came.
Some firearms will have slight differences, and in some cases the washer will help seat the SCS against the back of the bolt carrier group.