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JP Rifles’ Silent Captured Spring (SCS) is one of those things that I can’t imagine living without. This captured buffer weight plus recoil spring system for the AR-15 and AR-10 completely eliminates the Mattel-like “SPROING” sound and grating, scratchy-squeaky feel of a standard buffer and spring setup. Additionally, it’s highly tunable and ever so convenient . . .

I don’t know about you, but it’s fair to say that I detest the sound of a standard AR-15 buffer and spring setup. Not just the sound, actually, but that jankey, toy-like, scratchy feel that conducts through the receiver extension (buffer tube) and/or stock and right into my face and shoulder. That chintzy clang and springy sproing and rebarbative rattle can be heard and felt both when manually cycling the charging handle and when firing.

Add a suppressor and it’s even worse. Shoot a suppressed, 9mm AR-15 or a subsonic .300 BLK AR-15 and it’s enough to be distracting. Sure, maybe I’m a little OCD, but the freaking spring noise is louder than the gunfire and it’s f’ing annoying! And it’s a real firearm, dagnabbit, so why does it sound and feel like a spring-powered airsoft toy?

Unfortunately I pretty much completely failed at capturing the audible difference between a factory buffer setup and the JP SCS. Getting a microphone to pick up what the human ear picks up in addition to what’s conducted through the bones of the jaw, plus getting that to play back in an equivalent fashion over speakers or headphones proved highly difficult (plus, your specific speakers/headphones will affect your ability to hear what’s in the video below). This quick clip is as close as I got, with an external microphone placed on top of the buffer tube.

Although some of the difference is audible in that video — maybe 10% of what you hear/feel in real life — and sounds to me like the slamming of palms against a loose, chain-link fence (audible only with the standard setup), you’re unfortunately just going to have to take my word for the fact that it’s a massive difference in real life. Night and day. Toy sproing and scratch and fence rattle noise vs. complete and total silence from the buffer area.

And, if I haven’t made it clear enough already, it’s not just noise but feel as well. Now, whether pulling the charging handle or firing the rifle, it’s smooth and nice. Gone is the vibration and spring binding, scratchy sorts of things that can be felt through the cheek, jaw, shoulder, hands, etc. It’s just oh-so-smooth.


Now if sound and feel seem a bit nitpicky, and improving just those things maybe isn’t worth the cost of entry, the SCS has other benefits as well. Least important, probably, is that convenience factor I mentioned above. As the SCS is a self-contained unit that’s just about the exact length of the buffer tube, the buffer retainer (the pin that sticks up in front of a normal buffer and prevents it from shooting out under spring power) is no longer needed:JPSCS-retainer

Not a huge deal, but since the SCS is over a hundred bucks it’s pretty nice to be able to remove it from one rifle and drop it into another in about 10 seconds. No buffer retainer also makes swapping and adjusting receiver extensions faster and easier.

Also very convenient is the fact that the same SCS can be used in carbine- or rifle-length receiver extensions. The SCS itself is carbine-length, but it ships with a spacer that allows it to be run in a rifle tube. More bang-for-the-buck with the ability to quickly swap it between all of my lowers.

More importantly, the SCS smooths out the actual operation of the firearm, minimizes bolt bounce, and can be tuned to suit a rifle’s specific operating system. JP offers different weights to allow for changes to the mass of the buffer and also offers five different spring weights for selecting the perfect recoil spring power. That said, I’ve put multiple thousands of rounds through the standard AR-15 setup through a handful of rifles without a hitch of any sort, but the option to custom-tune it is great if you’re looking to really dial things in and end up with the smoothest, lightest-recoiling action possible.

One item of note is that the center “guide rod” of the JP SCS does not compress, and remains full-length while the buffer weight is compressing the spring:

JPSCS-compressedOn nearly all AR-15 and AR-10 rifles, this is a non-issue. The bolt carrier is hollow in the middle and it simply surrounds that guide rod as it cycles into the receiver extension. The notable exceptions are bolt carriers from PWS, as the extra mass added at the rear of PWS’ carriers restricts the diameter of the opening too much.

Additionally, most 9mm AR-15 bolts have an extra weight that’s pinned inside of the hollow channel. That weight will have to be removed in order to use the JP 9mm SCS, which is the one seen on top in the lead photograph. The weight in my CMMG carrier came out fairly easily, and the 9mm SCS has run flawlessly in that setup. There’s more than enough weight in the SCS buffer to make up for removing the pinned-in carrier weight, and the entire blowback action feels smoother and more solid. Some 9mm bolt carriers are solid at the rear or have a welded-in weight and, in those cases, the SCS isn’t an option.

For those on a budget, JP’s Custom Centerless Ground and Polished Operating Springs (bottom of this page) offer a shockingly large reduction in spring noise and feel compared to any other recoil spring that I’ve tried — and I’ve definitely shot plenty of parts kit and other generic ones plus a couple Brownell’s, DPMS, and otherwise-branded springs. Apparently just getting the diameter exactly perfect and polishing the springs to a mirror finish is worth the time and effort. If $139 for an SCS isn’t in the cards, or isn’t for the entire AR collection, the $19 cost of entry for the centerless ground springs is fully worth it.

Ratings (out of five stars):

Fit: * * * * *
Spot on. Universal for carbine and rifle. No buffer retainer needed.

Functionality: * * * * *
Improved over the standard recoil system in every last way. Plus it’s fully tunable.

Overall: * * * * *
5-stars. I love the SCS. Even if you haven’t been bothered by the grating twang of a standard recoil system, the SCS is one of those things that, once you try it, there’s no looking back. That sproingy twang will be torturous in comparison to the smooth sounds of silence.

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  1. I’ve neen running one of these on my mk18 clone for a year now. I don’t think I could ever go back. When you combine it with the third position on a TAC-CON trigger, the results need to be felt to be believed.

  2. We get it. Scratchy feelly thingy sound from springy buffer tube bad….other thing good….got it.

    Good thing I wear hearing aids and ear plugs otherwise I just wouldn’t have known.

    Thanks for the update.

    • When your ear plugs are really good is when I notice it the most. That clangy scratchy sound (good description) goes into your ears through your jaw bone. I find it very annoying. Haven’t gotten around to getting one of these, but it’s on my list of things to get someday. Glad to hear it has good reviews.

    • Yeah ear protection makes no real difference. When your cheek is against the stock, the sound & feeling are mostly conducting through your face. Then it’s even that much more pronounced when you tack on a suppressor and reduce the gunshot volume way down. Again, ear pro or not the noise of the spring is obnoxious. Especially once you shoot w/ the SCS and realize just how much annoying sh*t you’re hearing/feeling that you don’t have to. All of that aside, the action runs more smoothly and solidly — less jerky and inconsistent — w/ an SCS vs. standard buffer & spring.

      • So did you use the standard or heavy version? What would be a reason for running the heavy?

        I run Spike’s heavy buffer now but that was done to reduce felt buffer noise (powder inside the buffer instead of a sliding weight). I imagine the heavy JP is meant for another purpose?

        • I just run the standard one, and I’ve run it with the full gamut of .223 and 5.56 as well as subsonic and supersonic .300 BLK without issue. I suppose you’d go with the heavier weights to slow the action down for some reason. Could be paired with a more powerful spring to better handle calibers that are outside of the AR-15’s actual design intention like .458 SOCOM, .50 Beowulf, and other cartridges that are way more powerful with way more recoil than 5.56… but there are other reasons to tinker with the gas system, BCG weight, buffer weight, and buffer spring power.

    • Grease the spring. I use Mobile 1 synthetic grease on the main action spring on every gun I own. Works wonders, it’s cheap, and a tube of it will keep you in business for years.

      • The red stuff? I’m a fan of that as well. I actually did usually grease my AR springs but it still leaves a lot on the table compared to the SCS. Not in cost, of course, but the improvement is only a fraction of what the SCS provides.

        • Yep, the red stuff. I use on every part that reciprocates: slide rails, bolt lugs, raceways, cams, etc. Springs are a reciprocating part. I’m sure the JP SCS does what it’s designed to do, I’d just rather put the $140 towards a new gun or reloading components. Truth be told, while I own a nice LMT, I don’t even enjoy the AR that much… So maybe I’m biased against all of the accessories that everyone seems to “need.”

        • hmm that’s a good point. The plugs I wear are 33 dB NRR. That doesn’t technically bring most rifles down to hearing safe either. I guess I didn’t “do the math” in the same way because 33 NRR plugs seem significantly quieter to me than a 33 NRR suppressor. That’s odd. Maybe they’re effective in different frequency ranges and a suppressed 5.56, for example, feels and sounds louder even if technically my ears should be getting the same dB with no suppressor but ear plugs in.

          I was actually just talking with the owner of a shooting range near me about how we’re both a little OCD with hearing protection and double up on plugs & muffs when shooting at the indoor range and do the same whenever possible when shooting rifles as well. I often forgo the muffs due to cheek weld issues, but on some rifles it isn’t a bother and if that’s the case I will double up. Unfortunately, a lot of dB does get to your ears through bone conduction, especially with a cheek weld on a rifle stock, and hearing damage over time is highly likely no matter what. Except… shooting suppressed + ear pro. I basically refuse to shoot supersonic rifle rounds, even suppressed, without plugs in. Same “doubling-up” as plugs + muffs, basically. Plugs + suppressor. Another reason they should be legal everywhere and either treated like normal firearms (gov’t gets its excise tax) or treated like any other piece of metal out there and available for purchase off the shelf just like an optic or other accessory or a stapler, etc etc

          Coincidentally enough, I had a full-on hearing test two weeks ago. Still well above average. But your hearing does not grow back, tinnitus is a f’ing horrible thing, and volume levels do NOT have to be even close to causing discomfort to cause hearing loss. Plenty of truck drivers out there who are totally deaf in the frequency ranges of wind buffeting open truck cab windows. I’m thankfully approaching like 75% deaf in the frequency range of my wife’s voice 😉

        • Jeremy, whoa! I’m not thinking that bone conduction causes hearing loss. Are you sure? I thought we were damaging hearing due to eardrum damage, which bone conduction would not affect.

  3. The only thing it needs to make it perfect would be to have it stamped in the front “This Side Towards Enemy”…

    To match the ‘This End To The Rear” stamped on the back…

  4. schiiinngggg is the sound of freedom.

    Too much? Ok, I like that sound. it reminds me of my days in green with boots I had to shine.

    • I prefer to avoid reminders of those days. You would not think that a job where you mostly play with guns and explosives and hang out with your friends could suck… But…

  5. I’ve got two of these. One in a rifle, one in an SBR. They aren’t cheap and you can argue the merits all you want but these things are great!!!! Contemplating the 9mm version.

    • Absolutely worth it in the 9mm. It’s excellent in my 5.56 and 300blk as well, but my little 4.5″ 9mm eats all flavors of ammo after switching to the JP buffer. Used to be a little picky feeding with the old A5 setup I used, now it’s thousands of rounds with no FTF.

  6. How would this work with an LMT piston gun? Their bolts have a differently shaped hollow.

    • You may want to confirm w/ JP by measuring the inside diameter of the hollow part (in the event that they don’t already know whether or not it’s compatible). They do only mention PWS as being incompatible on their website and, FWIW, it functions fine with my Adams Arms piston BCG and that has some anti-tilt stuff at the rear that changes the shape a bit.

  7. I too couldn’t stand the scratchy ‘sproing’. Drove me crazy! So I put a JP SCS in my RRA – and I absolutely Love it! It’s never coming out of that rifle!

    BUT… it does add a little weight…and on my next build (a DD M4V7) I really wanted to go as light as possible and stay as ‘mil-speccy’ as possible too, so, I did a little research and found an alternative solution:

    A Tubbs Flatwire Spring, wiped down with a little white lithium grease, coupled with a Spikes Tactical ST-T2 (phosphorus) buffer.

    Came to me from a dude with infinitely more experience than myself, and works like a charm. Silent as a church mouse, smooth as a babies butt and quite a bit lighter (on the wallet as well).

    Just thought I’d pass it on, FWIW.

    • You can also punch the pin out of nearly any standard buffer weight and pack something in there so the weights aren’t able to rattle around, then put the bumper back on and drive the pin back through. Gets rid of the noise from the buffer. However, that rattling weight is there by design and imparts a “dead blow” effect to the BCG, which greatly reduces bolt bounce. The JP SCS has a similar functionality but isn’t noisy about it.

      • Ahh cool interesting. Haven’t heard that one before. I actually already had the Spikes ST-T2, so worked out good. Think they are less than $40 shipped anyway and a damn fine buffer. The JP SCS still might be a hair ‘smoother’ than the Tubbs/Spikes combo, but both get rid of the sproing completely. Still love the JP SCS. I just got on a lightweight kick after that RRA build and haven’t looked back since. Anyway, just my .02c

    • I have the Tubbs Spring set in all of my ARs. I bought this captured spring on a whim, and was quite disappointed.

      The noise reduction is nice, but not that big of a deal.

      The weight increase was noticeable in my 11.5″ sbr.

      If you run it without the capture pin, you have to worry about it slipping out if you need to open the upper up to fix a malfunction. This is twice as bad with a piston BCG (since some have a spring in the bolt to keep it in battery, and pushes the bold back when the upper is open).

      I could have bought two Tubbs flatwounds and nice buffers for the price of the Captured unit.

      I can see the appeal for shooters that use standard wire springs, but I’ll pass.

      • Also, the Tubbs springs have an insane service life. Chrome Silicon alloy is the same material that valve springs are made from. They can run in excess of 500,000 compression cycles before losing their tension level. The standard wire springs begin to lose theirs after a couple of thousand.

        • Yeah, I guess ultimately I felt better about running the Tubbs set up on a potential go-to rifle as well, mostly because of the weight savings and reliability/longevity. The JP SCS stays in the RRA, but still love it. One thing the JP SCS does do is allow you to tweak the action, so would be great for getting a 300 BLK shortie to run right with subs/supers + a can / getting a problem shortie tuned up right, etc.

    • Haha, nice timing. See my post above you. I run both, and love both. Both (to me) are equally ‘non-sproingy’. The JP has some cool things going for it though, and might be cooler on a suppressed 300 BLK shortie, allowing you to adjust it to exactly where you want it, etc. But if you’re just looking to get rid of the sproing on a 16″ middie or carbine, stay light, a wee bit more ‘mil-speccy’ and save a few bucks – I can’t say anything but great shit about the Tubbs Flat wire spring, wiped down with a little white lithium grease, coupled with a ST-T2. That’s what’s running in my ‘go-to’ rifle.

      • Robert’s talking about the Tubb’s spring vs. the $19 JP Centerless Ground springs. I can certainly pick up a Tubb’s and do a comparo, as I have a couple of the JP ones around here somewhere, but there’s no way in hell I’ll be able to quantify the difference or capture it on audio, etc. It would just have to be my feedback on which one feels smoother and sounds quieter. Assuming I could even feel or hear a difference at all, which is a big “if.”

        • Ahh gotcha, didn’t see that. Yeah… I was talking about the Tubbs CS Flat wire spring. If I had no worry about weight, or wanted to tune the action on a shortie, I’d go JP SCS every time. It is a pretty awesome device, and gets my full endorsement – even with the Tubbs/Spikes/Lithium combo option available.

      • A better question is, why don’t they team up with Tubbs (or someone else who does the same thing), and offer this with a CS spring? It would be the best of both worlds then, no?

        • Lol, that would be a good experiment. Replace the spring in the JP with a flat wire Glock spring.

  8. My comment didn’t show up?

    Anyway, I have one rifle with the JP SCS and one with synthetic grease on the spring. If you charge the handle and shoot them side by side, you can’t tell the difference. I feel silly for buying the SCS when a dab of grease for pennies does the exact same thing and weighs less.

      • I should have been more clear. I appreciate that springs of different strengths/weights are available for tuning, I’m concerned about adding ounces to my rifle and I doubt changing the spring itself would make a difference in that regard. I meant to ask about the measured weight (like grams or ounces) of the whole buffer, weight, rod, and spring assembly. Everything in the buffer tube. I’ve avoided some of these improved buffer spring systems or tubes (and parts in general) in the past because they added a couple of ounces to the rifle and with AR-15s I have always been counting ounces to keep the rifle as lightweight as I can. I appreciate the value of a system that makes shooting more comfortable or enjoyable, maybe even more shootable in competition, but if it even slightly decreases my ability to fight with the weapon (by being just as functional, reliable, practically accurate, and combat effective as before but a little heavier) it’s usually just not for me. I just want to know how much heavier or lighter my rifle will be if I install the JP Enterprises Silent Captured Spring system. If I know, then I can decide if it’s worth the weight for my rifles. It probably is for most rifles, but I wonder about the ones intended to be “ultralight” that I favor. If it adds a couple of ounces I’d probably prefer to just install a superior spring on such a rifle, keep the light weight, save $120, and live with slightly more scratchiness and noise from the buffer after each shot. When looking at any new rifle part replacement or accessory, weight is the third thing I wonder about, after reliability and utility.

        Any experience with that JP Low Mass Buffer?

        • Oh sorry, haha. Yeah it’s going to be a bit heavier due primarily to the action rod. The standard SCS — and remember that you can add weight to it by swapping steel weight rings out for tungsten ones or can remove weight by removing or lightening some of the steel buffer weight rings — weighs 7.25 oz. …that’s right on 2 oz heavier than a typical parts kit buffer & spring. But you can remove the buffer retainer and drop a few grams 😉

          I haven’t tried their low mass parts like buffer, bolt carrier, etc.

        • Thanks for the info! I appreciate the effort you put into responding to the comments on your reviews. I’ll probably buy that spring and see how it is. 2oz for the full kit… I might be able to spare that on some guns. Heh! For a range, competition, or dedicated home defense gun it would be nice. No current plans to remove the buffer retainer, I haven’t yet gone off the ultralight deep-end into gram-counting. I do occasionally read blogs about ultralight backpacking by true gram-counters, but I still use a (relatively very compact and light!) electric toothbrush. I haven’t taken to using only a toothbrush head with the handle chopped off! Or weighing my underwear and cutting pockets off of my pants. I’m not competing to have the lightest gear, I’m only doing it for function, and if I can save two ounces here, two ounces there, etc. and end up with a gun a pound or two lighter with the same functionality, I’ll be in better condition after marching or hiking a couple of miles with the gun. Or perhaps just to offset the extra weight of a heavy, high-quality scope on a long-range rifle.

  9. This is why I come to TTAG, great article and great to see others enjoy the product as well. I need to put it on my “to buy” list.

  10. Yes, the “SPROING” used to get on my nerves, too, as did the rattle. But I’ve gotten used to both, and now look at the AR’s audible follies as somewhat endearing, sort of a ballistic Gerald McBoing-Boing.

    • Basically, it just has to clear the diameter of the bolt head that you see in the last photo in this gear review. As long as that bolt head and the rod behind it can fit into the bolt carrier, it’ll function. The OD of the flange on that bolt head is 0.444 inches.

  11. “And, if I haven’t made it clear enough already, it’s not just noise but feel as well.”

    Quality buffer tube. LMT, BCM, Larue of the 7075 type metal. Run your finger in the buffer, if you feel tiny ridges from the “extruding” or whatever process they use, its a cheap buffer tube. Mine are smooth with BCM tubes.

    Chrome Silicone buffer spring, they come in various tensions but I just use the standard. Not only are they smoother/polished they last 200,000 cycles vs 5,000 for the standard spring.

    CLP on the spring.

    My AR’s are smooth cycling with the stuff above. They don’t make that springing noise.

    A friend of mine bought that JP deal for $$$. He has OCD and tried to adjust it perfectly, only to have it short stroke and FTF. While the rest of us just kept shooting. It is also heavy in comparison.

  12. I put one in my latest 5.56 and 6.8 SPC AR builds. I like them and look forward to moving to a free state from Kommiefornia one day and suppressing them. I won’t go back to a plain spring and buffer weight.

  13. This made me remember my very first time to shoot an AR rifle in 5.56. I had Dave Clark muffs on and the shell of the muff against the stock transmitted the “slinky” sound right into my head. I had shot one round and asked the rifle’s owner, what was that sound coming from? He looked at me like I had 2 heads. I was shooting at a club to qualify to get a M1 rifle from what was then called the DCM back in the 1970’s?

  14. I put a JP SCS on my “Franken-rifle” because I couldn’t stand the annoying “sproing” either. Personally I love it. In regards to weight, one thing ya’ll might want to consider is WHERE the weight is being added and how this effects weapon maneuverability and balance… If you were adding 2 or 3 ounces to the front of your rifle (think light/suppressor/fore-grip, etc.) then it’s going to slow down your transitions from target to target and make the weapon “nose-heavy”. But – by adding the weight to the closest point on the rifle to the shooter (in your buffer tube) these two issues are irrelevant. If you’re gonna add weight to your rifle, you want it towards the butt! My rifle handles just as well (or better!) after adding the JP SCS, and the added weight is pretty negligible.

  15. I bought one for my suppressed Stag lower/Radical Arms .300 Blackout suppressed with a Silencerco Omega. I did several upgrades at the same time. I added the SCS and the new Timney 3lb trigger at the same time. Since the addition, I am getting about 33% light strikes. I sent the trigger back to Timeny and they upgraded the hammer/spring to the AR10 version. Still 33% light strikes. I upgraded the firing pin to titanium, scraped the bolt to shiny clean and checked the headspacing. All good. Firing the Remington subsonics. I am going to swap out the SCS for the stock buffer assembly to test it this weekend, but my gunsmith thinks I am getting “bolt bounce” from the SCS and he believes that is the cause of my issue. I have sent JP 3 emails and left voicemails for them to suggest a possible cure, no replies in over two months. A bit fed up with the customer dis-service. BTW, I did leave the buffer detent in place, didn’t want the SCS to fly out or impede takedown during disassembly. Any suggestions?

  16. Has anyone tried the JP SCS in a Lonewolf G9? If so is it still reliable after removing the weight?

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