Accessory Review: KynSHOT Hydraulic Buffer Tube

    I enjoy shooting shotgun (or maybe I should say I enjoy the *boom* and the target obliteration that it causes). But I don’t like shooting “a lot” of shotgun and, additionally, there is a reason you don’t see shotgun courses that run 500 rounds in a day. It is just a lot of force to absorb. I have some shoulder damage from some earlier days of being rowdy and, also, I don’t hunt things for which a shotgun is an appropriate platform. I carried a Remington 11-87 when I used to do EP work. And when I was downrange we had a couple of Remington 870s for breaching. That is really the extent of my “working” history with shotguns.

    A couple of months ago my editor approached me about testing and evaluating a product from KynTec. Kyntec is coming to market with a hydraulic buffer tube for a Remington 870 equipped with Mil-Spec pistol grip and adjustable stock (e.g. Mesa Tactical). In reality it should work with any platform that will accept a Mil-Spec AR stock (though it has a pretty heavy compression for anything other than a shotgun).

    KynSHOT as it arrived.

    KynSHOT as it arrived.

    I got the tube in the mail, and it was a pretty simple component. Basically a tube in a tube threaded on one end and with an adjustable stock stop rail. Both cylinders are constructed of a hard coat anodized aluminum. It is rated for a compression stroke of 0.875 inches. The compressed spring force or 72.8 lbs is nearly double the extended spring force of 34.0 lbs. What does that mean? It takes some strong force to compress.

    Preparing to swap the buffers.

    Preparing to swap the buffers.

    Not having my own 870, I borrowed one with the appropriate adapter from a relative and did the install. Installing it was pretty easy–the KynSHOT simply goes in place of the standard extension tube. Break out your handy AR armorer tool to handle the castle nut and swap out the tube.

    Installation.

    Installation.

    Installed, left side.

    Installed, left side.

    Installed, right side.

    Installed, right side.

    It is difficult (and expensive) to take hard measurements of the live round dynamic force. It requires specialized equipment; equipment to which I just don’t have access. What that means is that I will provide my observations in a more subjective manner (down in the “Shooting Evaluation” section).

    The evaluation model (the KynSHOT Gun Buffer) I was sent was an early prototype and was hard set to a “mid-range” dampening position. It is possible to manually compress the buffer but it definitely takes a good amount of force. The production model is going to have three user selectable settings which vary the hydraulic damping by about 15% with each setting.  This will allow the shooter to adjust the unit for the particular load for the day – low for bird shot, high for solid slugs, etc. This feature is unique to the KynSHOT. The measurements done by KynTec estimate the reduction of the perceived recoil by 75-80%. They summed it up as “our buffer makes it practical and possible for a 12 year old, 95 pound girl to shoot a 12 gauge without fear”. Read that “fear” as referring to the shooter; a 95 pound, 12 y/o with a full-size tactical 12 gauge shotgun terrifies me…

    One major consideration for hydraulic systems is operation at varied temperatures. Depending on the type of fluid, you could have a significant reduction in operability at cold or hot temperatures. KynTec has taken this into consideration and has designed the system to work in an extremely wide operating range. They state that the damper will perform nearly identically from -30F through 130F.  They have units undergoing evaluation in Arctic climates, and those same units spent the summer in Texas.  Subjective feedback from those environments is that shooters report the same “feel” regardless of which climate. Personally I have fired an 870 at 120F+ and it operated fine; I have no idea what the weapon itself (irrespective of the buffer tube) would do at an extremely low temperature.

    Shooting Evaluation

    I ran the shotgun in three configurations: with the original stock, then with the pistol grip and adjustable stock, and finally with the KynSHOT. I split my shoot over two days. I did about 10 shots of 00-buck with the two earlier configurations (the non-KynSHOT setup) on the first day as a sort of baseline.

    Fully installed with collapsable stock.

    Fully installed with collapsable stock.

    I went out the second day to do the test fire of the the KynSHOT. I fired 24 rounds of 00-buck, and 4 1-oz slugs with it. My wife shot 8 rounds of 00-buck with the KynSHOT installed. I would have shot more (and re-configured to the standard AR Buffer tube), but I had an “armorer” induced problem. Basically I screwed up and did not correctly torque the anchor bolt on the MESA Tactical adapter, and then, to compound the problem, did not bring ANY tools to fix the problem… The adapter ended up getting loose over the course of fire. This was not a failure of the component, just me… 🙂

    Shooting it was definitely interesting. There was very little recoil. It was very comfortable to shoot (as comfortable as you could be with a shotgun anyway). One thing I did notice was that it was more challenging for me to rapidly cycle and re-chamber the weapon after every shot. If you are used to using the recoil to “assist” you when you operate the action (using a push/pull method for rapid followup shots), you may find that the KynSHOT changes the timing a little bit–so definitely something to practice if you install one.

    My wife (while not 95 pounds nor 12 years old; though I do have a solid 120 pounds on her–and don’t ever ask her age…) had no problem operating the weapon. She’d had a bit of pre-existing fear about shooting a shotgun as her sister had acquired a healthy bruise and discomfort from shooting my 11-87 a couple years back. After shooting the KynSHOT, her quote was “Oh, that’s really not that bad.”

    Conclusion

    Overall I think this is a great product. It really reduced the perceived recoil for me. My wife did not mind shooting it either; she hated my 11-87 (which I made her shoot the same day after she fired the KynSHOT). I’m not going to go out and put 500 rounds down range with it, but I don’t think a couple hundred would be bad at all.

    KynShot offers a 10 year/1 million round warranty on this buffer (as they do on their rifle models).  Aside from blatant abuse of the weapon, there is no reason why it shouldn’t be handed down from generation to generation. And if you are wealthy enough (and determined enough) to put one million rounds through a shotgun, power to you.

    KynTec will be offering the KynSHOT buffer both standalone and as part of an adapted telescopic stock conversion kit.  The exact contents of the kit are still being defined, but they state that they will select only premium components to go with the KynSHOT.  It will be offered for sale through their authorized resellers, and also on Amazon.com.

    Pros

    • 10 year / 1 million round warranty
    • Simple design
    • Adjustable compression (on production model)
    • Easy Install

    Cons

    • Need to work on your push/pull round cycling as the timing “feels” different

    Tom is a former Navy Corpsman that spent some time bumbling around the deserts of Iraq with a Marine Recon unit, kicking in tent flaps and harassing sheep. Prior to that he was a paramedic somewhere in DFW, also doing some Executive Protection work between shifts. Now that those exciting days are behind him, he teaches wilderness medicine and writes for a number of publications, including The Prepared, a site devoted to self-preparedness. He hopes that his posts will help you find solid gear that will survive whatever you can throw at it–he is known (in certain circles) for his curse…ahem, ability…to find the breaking point of anything.

    You can reach him at tom.r AT thefirearmblog.com


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