Quick KynSHOT questions (and answers) for the impatient :
- Does the KynSHOT hydraulic buffer reduce recoil? Yes, we have used 4 different Kynshot precision recoil dampers and found that all of them deliver a reduction in felt recoil.
- Did any KynSHOT AR recoil dampers fail to fit or operate? All of the Kynshot buffers that we tried fit in every AR matched the specifications for that Kynshot model.
- What did we compare to the KynSHOT precision recoil damper? For starters, standard carbine recoil dampers for AR-15 and fixed stock rifle recoil damper for AR10. Additionally, we compared the AR-15 Kynshot buffers to the JP Enterprises Silent Captured Spring (SCS) for AR-15 carbine.
Update: March, 2017
*While re configuring and AR15 recently I had a brief moment of panic when I realized that AR did NOT have a KynSHOT buffer installed. I had not realized until that moment that I truly consider a KynSHOT buffer a standard part of any AR build we do at Gear Report. That should tell you all you need to know. BTW, after a couple of years of hard use in various ARs shooting a LOT of rapid fire via SlideFire stocks, the KynSHOT buffer still operates like new.
Other AR15 / AR10 articles you might like:
With no shortage of parts on the AR platform that have enjoyed significant evolutionary progress over the years, the lowly Recoil Buffer seems to have lagged behind a bit. However, KynSHOT claims that their innovative recoil buffers for AR15, AR10 and select shotguns help reduce felt recoil up to 30%, while diminishing wear and tear on parts, improving accuracy, and decreasing the flinch reflex.
So, what does the “Buffer” do, anyway?
Short version: When a shot is fired in an AR10 or AR15, the buffer slows the bolt carrier group’s rearward momentum, then pushes it all forward again.
Long version is at the end of this article.
Most people I know put little, if any, thought into balancing the energy required to cycle the various parts of their AR’s operating system. They simply trust that the manufacturer got it right. In an ideal world, the energy diverted to push the bolt carrier group rearward will be just enough to allow it to return to full battery, and no more.
There are a variety of other variables that can influence the balance of the operating system, like gas tube length and/or diameter, variable gas ports, varied buffer spring rates, different bolt carrier group weights, varied buffer weights, lubrication and/or coatings to increase or decrease operating friction, etc. While all play a role, this review will focus on the role of the recoil buffer.
Manufacturers often design ARs to operate with a wide range of ammunitions. To ensure operation with lower powered loads, more energy might be diverted to cycle the bolt via a larger gas port. We call this over-gassing: designing the gas system to deliver quite a bit more rearward energy than is expected to be needed so that a load on the lower energy end of the spectrum will still create enough pressure to cycle the operating system. Often, the increased rearward energy will be either ignored in design, or countered with a stouter recoil buffer / spring. This scenario results in higher than needed operating forces, which cause wear and tear on parts, as well as contributing to recoil that makes accurate follow-up shots more difficult.
The other end of the spectrum is to under-gas the operating system, such that there may not be sufficient energy to fully cycle the operating system, leaving the AR out of battery and unable to fire. This is annoying for a target shooter and can be deadly for someone that relies on their AR for targets that fight/shoot back.
How can the recoil buffer help?
A quick internet search turns up a variety of current offerings that claim to be improvements of the standard buffer. However, most that I have seen focus only on adding weight to the traditional buffer design via inclusion of a more dense material inside the buffer itself to increase mass. Increased buffer mass will absorb more kinetic energy, slow down the rearward motion of the BCG and retard the forward acceleration of the BCG, but at the cost of having more reciprocating mass in the operating system. More mass moving in the operating system means a heavier rifle, and more wear on the contact surfaces. It can also amplify the recoil impulse, if not balanced properly.
Another trend, which looks promising, involves the use of a hydraulic shock absorber within the buffer tube to translate part of the rearward energy of the BCG into heat instead of transferring it to the shooters shoulder. By changing the precision orifices/valves and/or other design parameters within the shock absorber one can alter the rate at which the shock absorber compresses, how much resistance it provides to the compression, and how much of that energy remains available to extend the shock absorber, translating the stored energy into kinetic energy.
Advantages of hydraulic recoil buffers
One advantage that hydraulic recoil buffers have over standard buffers is the ability to effectively absorb a portion of energy so that energy is no longer available to push the BCG forward. In an operating system that is over-gassed, with no ability to adjust the gas system, this is one of very few options to reduce some of the kinetic energy that causes wear and it reduces felt recoil.
Another advantage is that in the gradual compression and extension of the hydraulic recoil buffer to make the transition of the BCG from still to rearward motion, from rearward to forward movement, and forward movement to still more gradual. Spreading the energy over a longer time period can dramatically reduce the perceived / felt recoil.
Sounds good, but does it work?
I like a good theory of operation as much as the next guy, but I am more concerned with actual operation. What better way to test operational efficacy than to install and shoot with them? KynSHOT was kind enough to send us 5 of their hydraulic buffers for testing.
|Model #||Designed for|
|RB5000||.223/5.56 super-sonic ammo in carbine length stocks|
|RB5000L||.223/5.56 sub-sonic ammo in carbine length stocks|
|RB5005||.308 super-sonic ammo in carbine length stocks|
|RB5006||.308 super-sonic ammo in rifle length stocks|
|RB5006L||.308 sub-sonic ammo in rifle length stocks|
Honestly, the answer was apparent on the first shot after replacing the standard buffer with a KynSHOT buffer. However, we still shot a few hundred rounds with the various KynSHOT buffers installed to verify consistency.
YES, the KynSHOT recoil damper works!
We have used two of the KynSHOT buffers in a variety of rifles, both in .223/5.56 and .300 AAC Blackout. The third, however, was for a .308 AR with a carbine stock. The rifle we intended to test this in was delayed waiting on a specific barrel. So, the .308 buffer went unused. When the .308 rifle arrived (the WMG Guns Big Beast WMD-10), we realized that the Luth-AR MBA-1 stock was mounted on a rifle length buffer, not the carbine length buffer that we had a KynSHOT for. While this was not an error on KynSHOT‘s part, they sent us the appropriate sized .308 rifle length buffer for testing AND even threw in a prototype buffer designed for low energy / subsonic rounds for review as well.
Having shot the standard .223/5.56 buffer in nearly a dozen lowers, all of our testers agreed that there was a marked reduction in both felt recoil and the ability to get back on target quickly. Using the most sophisticated test tool known to man… um… man himself (did I just call us all tools?) we would guestimate about a 50-60% reduction in felt recoil in the .308, and maybe 50-ish% in the .223/5.56/.300 blackout.
KynSHOT vs JP SCS
One of my big questions going into this review was how the KynSHOT would compare to the JP Enterprises SCS system… which operates VERY differently. I hoped for some clear differentiators in performance, but in the end, they felt about the same to me. We have both in our long term test pool and will update this if more shooting reveals any notable differences.
Update December 2015 from the Gear Report Facebook page:
“The WMD Guns Big Beast Hunting Rifle is the nicest shooting .308 I have shot. I wasn’t sure if the Kynshot buffer would make much difference. Truth be told, it would probably be more noticeable on a less refined rifle. However, there is a clear difference in the felt recoil and muzzle climb when shooting with the Kynshot. I took a the Big Beast to the range this weekend and put it in the hands of several shooters who had just shot a Savage .308 bolt gun. There was some real hesitation from more than one of them since they expected a big kick. Every single one of them was socked that this big .308 felt more like a .223 with a muzzle brake. The word “smooth” was tossed around rather liberally.
As for the whitetail buck I took with the , he was a one shot kill at 150 yards. Where the KynSHOT buffer plays into this is in NOT worrying about being hammered with recoil. I have zero flinch reflex when shooting this rifle, as I know the recoil energy is being managed.”
But it is hard to install the KynSHOT buffer, right?
If you really take your time and pay close attention to every detail, as you should on any firearms manipulation, you will be in for maybe a 1 minute installation… start to finish. I can remove a standard buffer from a working AR, replace it with a KynSHOT recoil damper and have the gun put back together in about 15 seconds, if I’m not in a big rush. However, my parents always told me that I was above average. Plan to spend a whole minute on the initial installation.
How to install a Kynshot recoil damper in an AR platform rifle:
- Make the weapon safe… all the good stuff like removing the ammo and putting it in another room, verifying that the chamber is empty, etc.
- Release the rear receiver pin, allowing the upper to hinge forward on the front receiver pin, and exposing the face of the buffer. You can remove the upper, but don’t need to.
- Depress the buffer retention pin so that the buffer shoots out of the buffer tube… or maybe it is better to use one hand to depress the buffer slightly in to the tube while pushing down the retention pin, so that the buffer does NOT shoot out of the buffer tube, but rather, can be eased out in a controlled and safe manner. You don’t need to remove the buffer spring from the buffer tube. Just let the buffer out enough that you can remove it from the buffer spring.
- Throw the buffer in the box of interesting improvised targets (my box has golf balls, old cell phones, shotgun shell hulls, etc.), as you won’t be needing it again.
- Slide the KynSHOT recoil damper into the buffer spring… pretty much the same way that the original buffer was installed.
- Push the KynSHOT recoil damper into the buffer tube so that the buffer spring retainer catches it and holds the assembly in the buffer tube.
- Close the upper receiver on the lower receiver and re-insert the rear receiver pin. And you are done. It took quite a bit longer to read this than it does to actually do it.
What else is there to say?
I trust that a lot of engineering went into designing the KynSHOT buffers and tweaking the different models for different uses. While I appreciate that effort, what I REALLY care about is how well it works. As noted earlier, they work well.
At our latest testing session Jason, who at the time was the only one to have shot the WMD Guns WMD-10 .308 with the KynSHOT buffer installed, told me that it was “Amazing”, and that with the KynSHOT buffer, “…felt like a .223 with no compensator.” That is a ringing endorsement if I have ever heard one. And I was able to shoot it one handed while filming through the night vision scope that night. Try that with full, unmitigated .308 recoil. Or, actually, don’t. It will probably break your camera.
The cost isn’t that bad at around $110-$120 retail, depending on model. It is a bit more than the other popular way to reduce felt recoil: muzzle brakes. I love a good muzzle brake, and may (or may not, as far as you know) enjoy the way people move away from the adjacent benches at the range when I shoot with an aggressive bake. However, muzzle brake add weight and often length to the rifle, don’t reduce any of the kinetic energy slamming around the action, and are really annoying to other shooters.
I think that a great compliment to the KynSHOT recoil damper would be an adjustable gas block… which is one of my favorite ways to reduce cycling energy by diverting less of it to cycle the action in the first place. However, be aware that you may need to check with KynSHOT on which buffer will be appropriate for you if you shoot reduced power loads (like sub-sonic ammo), with a silencer, or with the operating pressure turned down via an adjustable gas system. Any of those might require one of the “L” models of KynSHOT buffer… “L” meaning it is made for a lower power load or lower operating energy.
On my personal rifles I will use the combination of a KynSHOT precision recoil damper, muzzle brake and, in guns that will sometimes wear a silencer and shoot sub-sonic ammunition, an adjustable gas block… in that order. While I think the adjustable gas block could be considered a first choice, they are comparatively hard to install. The KynSHOT is the easiest installation of the 3 by a long shot.
We really like to buy American made products whenever possible. KynSHOT products are made by KYNTEC Corp. Because these buffers are ITAR regulated, ALL of its parts come from US sources. Scott Taylor, the KynSHOT president clarified this forme, as I had read on their website that some parts were produced in Canada. He said that “KYNTEC’s industrial products use some Canadian parts, but the recoil product line does not.” With friends from the Buffalo area I know that they sure need productive industries hiring folks to help with their struggling economy and raise their spirits, since their sports teams seem to specialize in the soul-crushing cycle of getting fan’s hopes up, just to shatter those hopes. Over and over again. 😉 So, we not only like that KynSHOT is American made, but also that their operation is helping a region that has struggled in recent decades.
Nice ammo, dude!
We were fortunate to have an arrangement with Ammunition Supply Company where they provided ammunition for many of our reviews. In return, we share our videos and reviews with ASC for them to use on their website. For this and our other .308 reviews ASC sent some bulk 7.62×51 military rounds, 2 boxes of Hornady TAP 168gr .308 Win, 2 boxes of Federal Premium .308 with 168gr Sierra Match King projectile,s as well as American Eagle .223 55gr FJM and XM855 5.56 NATO rounds.
Big thanks go to our primary Ammo Sponsor Defender Ammunition Company for supplying ammo for tests and reviews on an ongoing basis. For continuing use of KynSHOT buffers we have shot Defender’s 55gr FMJ rounds in .223 Remington, subsonic and supersonic .300 Blackout, and a couple types of .308 Winchester.
SIG provided the 77gr OTM Match rounds in .223 Remington (link) for ongoing testing.
Gorilla Ammo provided the 69gr SMK OTM rounds in .223 Remington for ongoing testing.
How recoil buffers work – Long version:
When the trigger is pulled, the hammer releases, striking the firing pin, whichg ignites the primer. The resulting burning gunpowder in the case creates high pressure behind the bullet which pushes the bullet down the barrel. As the bullet passes the gas port some of this high pressure gas vents through the gas port, down the gas tube to the upper receiver, and into the gas key on the bolt carrier. This impulse of high pressure gas pushes the bolt carrier aft, causing the bolt to unlock (rotate out of battery) and move aft, extracting and ejecting the spent case along the way. The combination of the buffer spring and buffer slow the rearward motion of the bolt carrier group as it moves aft, then pushes the bolt carrier group forward to strip another round from the magazine and push the bolt forward, where the cam pin causes it to rotate and lock into battery.