Currently running a Vltor EMOD stock on a 6 position anti-tilt POF carbine tube with a Enidine hydraulic buffer. Overall I'm happy with the function, smoothness and rate of fire shooting a variety of uppers, both D.I. and piston, and calibers.

Lately I've pondered switching to the A5 system but I'm not sure I'll gain anything other than a longer length of pull, which would be welcomed as I have orangutan arms. If I go A5 it looks as if all I need is the buffer tube and one of the A5 specific buffers since I have plenty of rifle springs and the EMOD stock already - does that sounds correct?

So what say you guys like me that use their M16 to turn money into noise and scare the hell outta dirt, A5 or stick with what I got?

I've done a lot of testing with this lately...have you seen my webpage?
http://c3junkie.com/?page_id=654

I knew you were running the Kynshot hydraulic buffers just didn't realize your data was so extensive. I'll read up, thanks.

In addition to the Enidine I have a 5.56 Kynshot buffer (not the the 9mm version) any thoughts on running it in the A5 tube?

It's too short.  You need the 9mm kynshot buffer for use in the A5 tube.   Amphibian runs the 9mm kynshot in both 5.56 and 9mm cmmg guard setups with the A5 tube

As mentioned in the link, all this testing came about as a byproduct of testing the CMMG radially delayed blowback in 9mm.  Trying to get it to be to have a slow cyclic rate yet be soft/smooth as an MP5 and not bouncy like a 9mm AR when you get it down that slow by throwing mass at the problem.

As I've posted several times, I've never really liked or been impressed with the Enidine 556 buffer and neither the Kynshot 556 buffer.  It was never that smooth to me.
I've come to realize that I think it has to do with them being too stiff..

#1...first you need to make sure your gun isn't overgassed.  There is only so much springs and buffers can do.  Optimize the amount of gas cycling the gun, then focus on springs/buffers not the other way around.
However, a lot of people don't do that.  They just throw heavy buffers in there and call it a day.  Sure it will run, but it won't be as smooth and all you are doing is dumping excessive crap into the action as well as not being optimal.

I think the standard Enidine 556 or Kynshot 556 are more applicable for overgassed guns or scenario's where you just can't control the cycling (like straight blowback 9mm).

I have documented various buffers on my site here: http://c3junkie.com/?page_id=430

Specifically reference some of the hydraulics here:
http://c3junkie.com/?page_id=430#hydraulic

What I'm trying to show you with the hydraulics is the amount of force required to compress the 'piston'.
I have not found this data anywhere online so I did all the legwork and put it on my site.

Both the old Enidine and 556 Kynshot are over 9lbs to compress.


Kynshot 5.56


Now the RB5005 is advertised as one of their 308 models.  Another member, 'HDSledge' purchased this one to use with his 9mm CMMG Guard and was happy with it.  (he didn't want to change to the A5 length buffer tube for whatever reason.)  It is the same length compressed as the RB5000 or any standard carbine buffer for that matter.  However note that it is in the 5lb range to compress and the weight is slightly heavier than the RB5000 ...close to an H2 buffer.  It is also fatter than the RB5000.


Now look at the amount of force is forward on the BCG from just the buffer spring strength:
A2 (old)  7.6lb closed, 14.5lb open A2 (new)  9.1lb closed, 16.7lb openTubb 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

I think that with around 10lbs of force from the buffer spring on a closed bolt that the hydraulics that are around 9lbs don't do much if anything on the initial recoil impulse.
Again, if you're gun is overgassed to begin with then these ~9lb hydraulics may help but I don't have any setups that are overgassed to begin with.

Now since I was trying to squeeze every bit of performance out of the 9mm CMMG Guard, every bit helped.  I found that changing from the RB5007 to RB5005 yielded about a 30 RPM increase in cyclic rate so I stuck with the RB5007.  I can't recall my numbers for 5.56.  However, I know I have a local friend that did his own testing and also decided to stick with the RB5007.  He has his own PACT Timer as well.

I just don't look at the cyclic rate, I try to perceive what is softer/smoother and that is also a factor for me but hard to quantify.

Also if you want to cheap out on the A5 length tube the PSA PA10 has the same internal length and is only $20.
http://c3junkie.com/?page_id=571


I have a lot of different setups for the 'M16' so I would prefer a buffer / tube / spring that works for everything or at least as much as possible.
The setup recommended in my link above works for almost everything.

Again, my recommended configuration for most setups is:
1.  RB5007 Hydraulic buffer
2.  556 Tubb flat spring
3.  A5 or equivalent buffer tube

However, their are some configurations that it just won't work in.
When using the belt fed Shrike, I use the same as above but use the 308 Tubb flat spring instead and get in the 600's in cyclic rate and very smooth.

For 7.62x39 using the MGI lower and unmodified AK drums, it needs the dead blow effect to push the rounds through those rough combloc steel feed lips and the hydraulics just don't do it for me and so I use a standard Vltor A5H2 or MGI buffer w/ spacer.
Note that 7.62x39 fed from Frankenmags are fine w/ my preferred setup.

For the 9mm CMMG Guard if I switch to the 300 BLK Tubb flat spring, it will drop the cyclic rate another 30 RPM.

Alright gentlemen it has begun. I stopped in at one of my local PSA stores and bought their $20.00 PA10 buffer tube, step one complete. Next I'll dig out the parts box and find a rifle length chrome silicon spring, pretty sure I have one. I may even have a flatwire spring - I'll have to check.

Then it's time to decide on a buffer, Vltor or Kynshot, sucks that nothing I have will work.

I appreciate all your work & advice on this subject amphibian.

Sure.  I highly recommend the Tubb flat wire spring.  Again, it is the only spring that is advertised to work in a rifle and carbine length tube (A5 is in the middle so obviously works with that also).  
If you read my page, I'm basically saying you reap the benefits of the A5 system with the flat spring.  Going to an A5 length is just squeezing a little more performance out.

Ten four on the Tubbs FW spring!

After reading amphibians research I have been using a UBR stock set up as A5 system.   Running the 9mm blitzkrieg buffer and Tubb 556 spring. In my Colt M16.  Runs great with 556, .22lr, and FO 9mm belt feed uppers.  Using a Geissele SSF trigger.   His information is excellent.

Thanks!...How do you like the RoF with the FO 9mm belt fed?  Insanely slow right.  
I posted a video of mine here: https://youtu.be/bRBjdyqlLaE

Don’t have anything to compare with. I’ve only used the blitzkreig buffer.  I didn’t get a regular A5 buffer. It does shoot smooth.

This is great info Amphibian, thanks for sharing!

Exactly what I was looking for in regards to running the set up I want for my m16.

I would go A5 tube, but I really don't want to break the factory receiver extension paint and staking on my original colt m16 carbine.  Sounds like I need to get ahold of a tubbs flatware to go with my h3 to atleast get some of the benefits similar to the A5 system.

As mentioned if I had to stay with a carbine tube, I'd go with the 556 Tubb flat spring and Kynshot 5005 which is the same length as a carbine buffer when compressed.

Amphibian thank you for clarifying that, it's been a couple of weeks since I last read this thread and your extensive research.  Since I bought my rr, ive been really concerned about using the right combo to have a smooth running set up for 5.56 suppressed that will also not put as much stress on the fcg pins in my lower.  I have yet to shoot the rr with any short barreled uppers due to this concern.  Just ordered a Colt 11.5 hrt barrel from shark arms today.  Cant wait to try it with the setup you recommend.  I might even use the govnah on that build, although my overgassed mk18 upper is crying for that gas block.

For 556, has anyone had a chance to compare the Surefire optimized BCG with its buffer and spring to the options in this thread?

Have you looked at these threads?: https://www.ar15.com/forums/Armory/Ferfrans-Bolt-Carrier/23-493014/?page=1
https://www.ar15.com/forums/Armory/Rate-of-Fire-Reduction/23-492565/

I think one or both of them has some people chiming in about buying the Surefire BCG.  
I posted my comments in there.  I'm not interested in it since I have so many configurations that are already setup for a standard length carrier travel and I'm very happy with how everything is running now in terms of smoothness and cyclic rate.  
I highly doubt the Surefire SOB using that mechanical buffer would be as smooth as what I'm running now and I've already got in the 600's with everything I'm running.
The other issue I have concern for is with the Surefire, you are now increasing the gap between the front of the bolt and rear of the bolt catch.  So more potential energy after the last round is fired and that BCG is flying forward impacting the BHO in the lower....with a BCG that also now has increased mass over a standard BCG....just like a 9mm blowback that is using a weighted 'carrier' and snaps BHO's.

I'm getting in the 600's, not increasing reciprocating mass, have full compatibility of a bunch of different configurations and I believe the hydraulics help to reduce shock upon intitial recoil impulse as well as forward.  I'm willing to bet there is way less impact on the BHO with my setup than the Surefire SOB setup.

All that said, I'd be happy to test one out but not on my dime.  I already have the FerFrans RRS BCG and while it really does reduce the cyclic rate, not smooth.

When you say this setup won't work with a beltfed Shrike, do you mean it won't cycle, or that the rate of fire is too high?

The 556 Tubb spring doesn't have enough force to strip the rounds off the links.
Now bear in mind that I have never resorted to stretching or lubing my links like some people have to do.

For me, just swapping to the 308 Tubb flat spring and I'm good.  As I've posted on several threads, domestic brass like LC M193/M885 strips easier from links than non-domenstic brass.  Including Wolf Gold.

Geissele has a released a new Super 42 rifle spring thats compatible with regular buffers, and works in the A5.

https://geissele.com/super-42-rifle-length-spring.html

Do you think that would offer any increase in performance vs the Tubb flatwire?

Bear in mind that the Tubb 556 and even the 308 spring will work in a carbine, A5 and rifle tube.  Cant say the same for the Geissele.  I haven't seen any numbers on the Geissele springs in regards to the amount of force is on the BCG when open vs closed like you can find on the Tubb springs.  I have nothing to back it up but I'm guessing the Geissele springs will have higher cyclic rates in full auto.
I'm sure it is high quality like all Geissele stuff is.

I've gathered everything except the RB5007 buffer, trying to wait and grab one on sale which may not happen.

Basically I'm building out a host lower for a DIAS and plan to visit my FFL/SOT and shoot some in a few days so I've hatched the following plan;
Install cheap PSA 308 A5 size buffer tube - check
Install Tubbs flatwire spring - check
Install regular Kynshot RB5000 5.56 hydraulic buffer - check

Now I need a 3/4" spacer to compensate for the shorter RB5000 buffer. So I chucked up a piece of HDPE in the lathe and turned a rimmed plug that rests in the end of the tube. The rim part is just under an inch O.D. and the rest of it is turned down to 3/4" diameter to fit inside the spring. Wish me luck............

Just bear in mind that in my second post above, I don't like the RB5000.  I cannot think of any configuration that really impressed me using that particular model.

Yeah I understand regarding the RB5000 amphibian, thanks for the reply.
I just want to get some trigger time with the sear in this lower so fabbed the spacer to prevent any damage to the receiver hoop. I'm a bit stubborn and keep looking for the RB5007 to go on sale somewhere.

I think you should have gotten the RB5005 instead of the RB5000 unless you just happened to already have the RB5000.
The lowest I've seen the RB5007 was when Botach had them on sale for $89.  They have the RB5005 for $100 now.

I've had the RB5000 for a while now along with an Enidine, got great deals on both. Now it's just a matter of watching for a sale to appear on the RB5007.

I finally pulled the trigger on the 9mm kynshot.  I paired it up with the tubb spring and A5 tube as you said and all I can say is wow!  Shooting a FA suppressed mk18 with crane spec .070 gas port is unbelievably smooth.  Looking forward to throwing my 9mm upper on there when time allows.  If anyone else is on the fence about this setup, don't be.  It's worth every penny and then some.

Great!  When you say your 9mm upper, do you a CMMG RDB or a straight blowback 9mm?  I wouldn't put a straight blowback 9mm upper on this setup.

I'm collecting parts to do an rdb upper now, but the only one I currently own is blowback. That should be safe in this configuration as long as I use a spacer to prevent bolt overtravel, correct?

Yeah...I just totally despise the straight 9mm blowback M16.  I have two of them and never use them.

Gotcha.  I'm really hoping cmmg can iron out the ejector spring issue you and others are having.  I haven't bought a builder's kit from them yet for just that reason. Thanks for sharing all your testing and data!  I'm still blown away how smooth and controllable this mk18 is with your recommended setup.

I haven't been shooting the SMG matches as often as I used to but I went to one back in August and another one today.  Ran the CMMG RDB back in August and today.  Got first place back in August and today.  My setup ran 100% both times....zero malfunctions....running my fixed ejector setup.

I've got some things I need to test for the spring loaded ejector so haven't totally given up on it....

Good to hear.  Hope you are able to release some of the info on your fixed ejector someday, or your friend decides to market the setup.  I bet shooting those matches is an absolute blast.  Very little in my area in the way of competitive shooting events, mostly just some long range stuff.

I've been using an Enidine buffer in my Colt 614 with standard carbine buffer and spring.  Will this work as well with the A5 tube and Tubb FW? Thanks!

No the Enidine is too short - you'll need a longer A5 spec buffer or the Kynshot 9mm unit amphibian suggested.

Thank you.

Just came back to post a thank you to amphibian and all who posted on this subject, this set up rocks!

Installed a RB5007 buffer and hit the range. It's hard to describe how smooth and flat the gun shoots with a very nice cyclic rate, not too slow yet still fast enough for that FA rush.