Just stumbled across this. Seems like it would pair well with a LMG type upper. Supposedly can reduce ROF up to 30%. In the video the rep is claiming 850 down to 588. I believe there is a similar BCG by Ferfrans that does the same thing.

Anyone try these rate reducing BCGs before?

http://www.recoilweb.com/watch-recoiltv-gun-room-surefire-obc-135516.html

I would certainly be interested in it. It kind of reminds me of this buffer and spring that I bought off the ee a while back where it had some weights that slid back and forth on the buffer itself. I'll have to put some pics up later when I get them.

I see that someone below put up the buffer that I've got. It's the older AAC rifle buffer. I would like to get ahold of an extra spring for it however. Regular rifle spring won't work and binds up on the rubber piece. It's like the rifle spring is slightly larger in diameter.
If someone knows, please let me know.

Two things.
1.  I would think that with this 'long stroke' design after the last round is fired, the BCG now has more momentum to slam into the BHO than a standard configuration and I guess could break it...this is what we see happening on 9mm blowback uppers..people making these long buffers to help prevent that.
2.  I personally have too many other configurations that rely on the standard stroke length and personally want to minimize how many times I'm swapping buffer/spring combos...

On that note, I've posted in other threads about my tweaking with the new 9mm CMMG Guard which is a delayed blowback operating system that uses a similar bolt and carrier configuration to a standard AR setup.   So the 'geometries' are the same.

Through discussions on these boards, I've done testing with what I think is best setup so for this system.  (at least for me running full auto and desiring a slow RoF and reliability)
This is documented here: http://c3junkie.com/?page_id=538

This combination is: A5 buffer tube, 556 Tubb flat spring and '9mm' Blitzkrieg/Kynshot hydraulic buffer.
The '9mm' Kynshot buffer is the same compressed length as a standard A5 buffer...below is HeavyBuffers.com's A5 buffer.


Now this is the '9mm' Blitzkrieg/Kynshot hydraulic buffer - compressed.


And now this is it extended:


I believe this hydraulic buffer is absorbing the initial recoil impulse and probably does addition absorption on the rearward stroke as well.
Combine that with the rifle length spring that isn't working as hard as a carbine spring and has a more consistent load, results in a smooth and slower running setup.
David Tubb has a great video explaining and proving the consist load of his springs here: https://www.youtube.com/watch?v=8fMVZbrnvu8&t=8s

A byproduct of this testing is that the same combination is working great for me in other configurations like my shorty 5.56 suppressed and unsuppressed configurations, 9mm Belt Fed FM9 and 5.56 Shrike (However with the Shrike I have to use the 308 Tubb spring).

The blow back FM9 was shooting fast and giving me trigger slap.
With this configuration, It smoothed it out and I now get: Rem 115 Gr Green box 518RPM

With my Shrike it also shot so fast I couldn't get singles and now I get the ROF's below and easily pulling singles (using 308 Tubb spring).
Short barrel M855 630 RPM
Long Barrel M855 693 RPM
I can pull singles easily with those RoF's.

My go to setup is a 12.5 suppressed upper and I can now pull singles with that.  I can't find my notes on RoF right now...I'll have to redo that...but I'm guessing I'm in the 600's.

Below is a picture of the old 'Counterpoise' system:

'D' is the weight that goes in the carrier.  Years ago, Biggerhammer.net (the original hosting site for subguns.com) had a review on their site years ago and it is no longer there...they had a positive review on the counterpoise and then later revised it saying that the sliding weight cracked and then a chunk of it fell into the lower...obviously causing issues of course.

I would be interested in trying the Ferfrans but would be leery the weight breaking off.

I kinda like the one below.
https://www.rainierarms.com/master-of-arms-ar-15-titanium-bolt-carrier-group-w-deadblow-kit/
They have 3 different ball weights...aluminum, brass, or tungsten but the carrier is Ti...don't think I want the LW carrier.  Would rather have a steel carrier with the ability to have that weight system and wave springs.


I think I have everything dialed in pretty nicely now...but I would like to try a carrier with a moving weight at some point in conjunction with the buffer system I have now...but not interested in increasing the stroke due to the two reasons I mentioned above and the fact that I'm getting some nice RoF's now.

Another picture from my site....maybe you are talking about the old AAC buffers?

I've never seen or used one, but I think the Ferfrans system is a standard carrier length.  It might pair well with the Kynshot and flat wire spring setup...maybe too slow for you.
[youtube]ztYtfm2oIfw?t=129[/youtube]

Yep...I'm gonna try one out.

Doesn’t the VLTOR A5 accomplish many of the same objectives as this Surefire system?

The great thing about the A5 is being able to use a rifle length spring.  The A5 doesn't increase the distance the carrier can travel like the Surefire setup does.  
You have the same distance the carrier can travel with a carbine or A5 or rifle buffer tube since that is restricted by the carrier key....which is why the Surefire setup uses a modified carrier key w/ only one bolt instead of two.

Now..if you forget about the A5 for a minute and consider the Tubb flat wire spring...both the 308 and 556 flat wire springs work in BOTH carbine and rifle buffer tubes.
http://www.davidtubb.com/tubb-springs
"Tubb Precision AR-15 Stainless Steel Buffer Spring (Fits both Carbine and Standard length stocks)"

I think with just that spring alone you are reaping benefits similar to an A5 system in a carbine length buffer tube.  Again, the Youtube video by David Tubb has quantifiable data showing the benefits with the load sensor attached to the buffer tube.

ar15.com member 'joshv06' watched the video and documented all the numbers...bear in mind these numbers were all obtained with a carbine buffer tube.  So the numbers should be a little lower on an A5 or rifle tube.
A2 (old) - 7.6lb closed, 14.5lb open A2 (new) - 9.1lb closed, 16.7lb open
Tubb Flatwire - 10.5lb closed, 16.3lb open
Tubb .308 Flatwire - 13lb closed, 16.7lb open
SpringCo White ? (standard) - 8.3lb closed, 16.3lb open
SpringCo Red (extra) - 10.5lb closed, 18.4lb open
SpringCo Orange (increased) - 13.9lb closed, 24.8lb open

Again the advantage of the A5 is that uses the rifle spring which has a good amount of force to keep the bolt into battery but the spring isn't working as hard as a carbine spring when looking at the numbers when the bcg is to the rear.  I underlined the Tubb flatwire in comparison to the rifle (A2) spring....both numbers are close....(again Tubb jammed a standard rifle spring in a carbine tube in his video to obtain these numbers).  
That round rifle A2 spring was getting close to being fully collapsed in that carbine buffer and not something you want to do.....which is why Vltor came out with the A5...giving that rifle spring some more breathing room....but the Tubb flat spring doesn't have that issue.  The Tubb flat spring isn't close to becoming fully compressed in that carbine tube....and the Tubb spring works even less when you extend the tube length which is what led me to the A5 tube.  I would go rifle tube but I want a collapsible stock.

Lastly, was the buffer selection and I've heard great things about the Kynshot hydraulic.  I wasn't sure about the 9mm version and took a chance that it would be similar in length to the A5 and fortunately it is essentially the same.

Regarding the Surefire SOB, the carrier does have an optimized cam path that sounds like the LMT enhanced carrier as well as the moving weight.  
I'm going to get a Ferfrans to test out how that runs with my setup but I guess I'll have to live without the optimized cam path.

just looks more pounding and harder to control...with my geissele trigger i can control burst perfectly...i can do a 3 round burst at will

also in that video it appeared 1/2 the time that m16 was pointing at the guy next to hims private parts.....at one point it was pointing 100% sideways right at him..gun safety should be flawless in any product video....id throw him off my gun range

to me? a product with out a need....for a subgun that you compete with slowing it down is often considered a plus....each gun has a point where its the smoothest....i prefer that point...this slowed down m16 looked like a jackhammer

Yeah...AAC made a few variations of those buffers...some could use standard springs while some versions are too fat.
Good luck finding a replacement.  I have a couple of them but they are for the carbine version.  Those springs are weak though for slow RoF.  They are notorious for not being strong enough to strip rounds off full mags.