KAK Industries has just come out with a new buffer design that includes a cushioning system in the head, similar to the way a hydraulic buffer works. Will this be a winner or just another snake-oil gadget?
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TL;DR: For a carbine buffer tube, the 9.8oz. K-SPEC is a great choice for recoil dampening. It performs nearly as well as the Gentle Recoil System (GRS) carbine tube options, and costs less. The longer A5 or JRC buffer tube GRS options still perform significantly better.
After a lot of experimentation and research, I found what I believe is the “holy trinity” to reducing perceived recoil in a blowback. The result was the development of my Gentle Recoil System (GRS) using off-the-shelf parts.
The Gentle Recoil System uses (1) recoil-reducing high mass to slow the action down, (2) an impact-reducing hydraulic buffer to dampen the impact of the buffer/bolt at the end of travel in the buffer tube, and (3) a noise-reducing flatwire spring. These three greatly improve felt recoil in a simple blowback 9mm. All the reports from people who have tried it have been extremely postitive except for one thing – the cost.
Hydraulic buffers are about $90, the spacer weights needed to increase the mass of the lightweight hydraulic buffers are about $20 each (typical setup needs 2), the flatwire spring is about $16, and the special longer buffer tube to fit all the parts is about $30.
Total: about $176 before shipping.
What KAK Industries has done is redesign their regular buffer bodies into 2-piece buffer bodies (kind of like this), and then put a spring system inside the head to provide impact cushioning similar to the way a hydraulic buffer works.
KAK applied this innovation to all their buffers. They now have PCC K-SPEC buffers, A5 K-SPEC buffers, and standard carbine K-SPEC buffers, all with the impact cushioning system in the buffer head.
Their heaviest PCC buffer is 9.5oz, without the need for the additional spacer weights required when using lightweight hydraulic buffers. Although it’s about 1.5oz. lighter than my standard Gentle Recoil System, 9.5oz should still do a good job of slowing the action. It’s high mass AND impact dampening.
KAK’s flatwire spring is included in the price, completing the “holy trinity” of perceived recoil reduction; high mass, impact dampening, and quiet buffer spring. The spring also comes with an installation tool since flatwire springs are notoriously irritating to put in and take out of a buffer tube. (The 3-D print file for the install tool is downloadable for free.)
Plus it all fits in a carbine buffer tube. No need for a special longer buffer tube like the original Gentle Recoil System.
The cost? About $84 for the most expensive and heaviest 9.5oz. K-Spec PCC buffer and flatwire spring. $109 if you include the buffer tube/castle nut/end plate. Lighter buffer setups cost less.
I purchased the 9.5oz. (because more mass = better blowback recoil feel) and took it to the range to compare it to a regular deadblow buffer and my Gentle Recoil System. After the Maxim RDB disappointment, I was (very) cautiously optimistic.
The buffer has a “phosphate” coating to protect it from corrosion, and arrives completely dry. All phosphated parts are “thirsty” and need plenty of oil, so I gave it a coat of oil before testing. The spring is fairly tight and rubs on the body of the buffer. Oiling the buffer helps keep it from binding or snagging on the phosphate coating.
The Buffer Specs:
Length: 4″ (proper length for 9mm)
Weight: 9.5 oz
Buffer weights: 3 tungsten sliding weights to prevent bolt bounce
Finish: Phosphate
Bumper color: Blue
The Spring Specs:
Coils: 26 active
Length: 12-3/8″
OD: 0.945″
Wire Width: 0.095″
ID (calculated): 0.755″
Bolt Open: 12.5 lbs.
Bolt Closed: 7.5 lbs.
The Testing:
To test the K-Spec, I wanted to compare it to similar weight and sized buffer combinations. I customized an 11oz. deadblow buffer by swapping 2 tungsten internal weights with steel weights to get it down to a comparable 9.3oz. I also chose the carbine buffer tube length Gentle Recoil System for comparison, but that’s only 7.3oz., so I also compared with a similar weight GRS (9.8oz), but that requires the use of a longer A5 tube to fit all the components.
- 9.5oz. KAK K-Spec/KAK Flatwire (carbine tube)
- 9.3oz. deadblow/Wilson Combat Flatwire (carbine tube)
- 7.3oz GRS (RB5000HP hydraulic + 1 weight)/Wilson Combat Flatwire (carbine tube)
- 9.8oz GRS (RB5000HP hydraulic + 2 weights)/Wilson Combat Flatwire (A5 tube)
I compared all 4 systems in 2 barrel lengths – 16″ and 5.5″ for subjective recoil feel and perception.
The Results:
16″ barrel PCC tests:
- Compared to a 9.3oz. deadblow/Wilson Combat Spring, it does reduce felt recoil. Not a big difference, but noticable. It takes the top harsh edge off the recoil.
- Compared to a 7.3oz. hydraulic GRS it’s pretty similar in feel. The GRS still has an edge in softness, but the impulse isn’t all that different.
- Once we increase the GRS mass to match the K-Spec by adding another spacer weight (9.8oz, but requires A5 length buffer tube to fit the extra spacer weight), it’s no comparison. The GRS feels noticably softer recoiling with the hydraulic buffer.
5.5″ barrel 9mm PCC tests:
- Now the difference between the K-Spec and the standard deadblow weight becomes more noticable. The K-Spec produces a significant drop in the felt recoil impulse. Doesn’t feel “soft”, but does feel better.
- Again, compared to the carbine tube-fit 7.3oz. hydraulic GRS, the recoil impulse is pretty similar with the GRS being a little softer.
- Adding another spacer weight to the GRS to match the K-Spec’s mass (and using an A5 buffer tube to fit it all) now puts the GRS in a different league. The GRS has a much softer recoil feel with the 5.5″ barrel.
Suppressor test:
- No real difference in gas or sound between a K-Spec and regular buffer of the same mass when using a suppressor, from what I could tell. Expect similar performance.
Conclusions:
Does it work?
- Yes! It does reduce felt recoil a bit compared to a deadblow buffer and the reduction was more noticable with a shorter barrel. The price is reasonable and it’s a simple 1:1 replacement for a similar weight buffer in a carbine tube. However, don’t expect MP5, or GRS performance from it. It’s better, but not a huge difference.
- A similar-SIZE hydraulic buffer+weight setup (fits in a carbine tube) is 2.5oz. lighter, costs more, and provides about the same recoil dampening feel, just slightly better.
- A similar-WEIGHT hydraulic buffer+weight setup does a better job of mitigating felt recoil, but requires a longer buffer tube and costs more.
If I was restricted to only using a carbine length buffer tube, I’d get the 9.5oz. K-Spec for PCC instead of the carbine-tube-length GRS. The K-Spec is better than a deadblow, it costs less than the carbine-tube-length hydraulic GRS, but feels almost the same to me.
If I was not limited to a carbine tube and could use an A5 or JRC tube, I’d get the GRS for greater felt recoil reduction. The GRS in the longer tubes is in a different league entirely.
I also think it’s safe to assume that the 9.5oz. K-Spec will do a better job with recoil dampening compared to just a plain 6.0oz. RB5007 or RB5015HD hydraulic buffer. I’ll need to test this in the future.
However, this is all from the perspective of felt recoil reduction. The softer-recoiling GRS setups cause more “bolt bounce” and so are less suited to competition shooting. Competitors may find the less-bouncy and mild recoil reduction of the K-Spec to be the superior choice.
Side Note: The KAK spring inertion/removal tool
The K-Spec comes with a spring insertion/removal tool because flatwires are hard to get over the buffer detent. They’re generally a real pain in the butt.
This tool is THE BEST! With how often I am inserting and removing flatwire springs for experiments and tests, it’s worth its weight in gold to me. Insertion and removal of the tool requires just a little attention, but it’s so much easier than struggling with the spring every time.
Future tests to be added:
During a future range trip, I plan on swapping the 3 tungsten weights in the 9.5oz. K-Spec with steel weights to test the recoil reduction of the lighter weight PCC K-Spec configurations (KAK has them in 6.9, 7.8, 8.6, and 9.5oz. options).
I also plan on comparing the K-Spec to a standard 6.0oz. 4″ 9mm hydraulic buffer for a direct 1:1 comparison of the buffer dampening.
Blowback9.com 