buffers w/non-milspec barrel ports

[steelonsteel]

I know the buffer thing has been ebat to death, and I DID search - for about an hour - but didn't get exactly the answer I was seeking.

Here's the issue.

So I have an SBR upper, and Ive been loaned for a week or so a differant upper to try. Here's the rub - it's an 11.5" upper from Rock River Arms. Yeah, I know - not really top of the chart - but for the price [read; free] I'll play with it.

Now, if I understand correctly, RRA tends to run their gas ports larger than mi-spec? Or perhaps I'm wrong on that?

If that is so, then theoretically, I should be using a heavier buffer - like say an H2... correct?

I have access to carbine and H buffers. But I'm wondering if shouldn't go ahead and buy the H2 for this, as I don't want to damage anything [since it's not really mine].

If I run too light of a buffer things will slam around and could potentially amage something right? or is the only drawback higher recoil?

I [I]think[I] I'm understanding this correctly, but once I got into port sizes I got somewhat confused.

Any insight or clarity anyone can offer would be greatly appreciated~

[Magic_Salad0892]

I'd suspect that port to be somewhere in the .080'' range, and as high as .093'' from what I know.

VLTOR A5 buffer system, Sprinco GREEN spring, and VLTOR's heaviest A5 buffer is the first thing I'd throw in it.

[BufordTJustice]

Agreed with Magic.

I'd also imagine a Tubbs flatwire CS action spring and an H3 buffer would help as well...at reduced cost from the A5 (with the A5/Springco Green being the ideal solution).

If you're planning on keeping it, I'd invest in the A5 setup as described.

[87GN]

Using the H will not damage it. I would shoot it with that and see what it does.

[az doug]

I agree with 87GN. Shoot it and see what happens. It will not hurt the gun. Possible bolt bounce if it is full auto or extraction issues. May not "ejection pattern" exactly where you want. Recoil may be a little more harsh.

I think it will run fine.

[markm]

Using the H will not damage it. I would shoot it with that and see what it does.

Agreed. It may not lock back on empty here or there, but It'll probably run fine.

H2 or H3 would probably be the quickest way to optimize function without switching the whole buffer system.

[Iraqgunz]

With a Venessa del Rio port like that I would run an H2 or H3. I would be more concerned as to whether or not you will get reliable extraction if you use real 5.56 ammo since RRA is known to have made some tight chambers in the past.

[BufordTJustice]

With a Venessa del Rio port like that I would run an H2 or H3. I would be more concerned as to whether or not you will get reliable extraction if you use real 5.56 ammo since RRA is known to have made some tight chambers in the past.

Holy Shit I just spit some coffee out! :D

Good one, Gunz.

On a related note, Ned Christiansen 5.56 chamber reamer would be great insurance and a huge step toward reliability.

Mike Pannone has observed that RRA's won't run very heavy buffers, even with full pressure NATO spec ammo. If the gas port on your 16" carbine-gas rifle is the size of Rosie O'Donnel's...um...gas port, and you can't run an H2 buffer with a std spring....your chamber is tight.

Note: My lawyers would like me to add for clarification, Rosie O'Donnel does not have a tight chamber.

[Iraqgunz]

That is interesting about RRA/ heavier buffers. Not so much about Rosie.... :D


Holy Shit I just spit some coffee out! :D

Good one, Gunz.

On a related note, Ned Christiansen 5.56 chamber reamer would be great insurance and a huge step toward reliability.

Mike Pannone has observed that RRA's won't run very heavy buffers, even with full pressure NATO spec ammo. If the gas port on your 16" carbine-gas rifle is the size of Rosie O'Donnel's...um...gas port, and you can't run an H2 buffer with a std spring....your chamber is tight.

Note: My lawyers would like me to add for clarification, Rosie O'Donnel does not have a tight chamber.

[kartoffel]

Hold on.... you're telling me gas port diameter matters?

All this time reading M4C and The Chart, I thought it wasn't something we were supposed to worry our pretty heads over.

[BufordTJustice]

Mike's article:

http://www.defensereview.com/m4m4a1-carbine-reliability-issues-why-they-occur-and-why-theyre-our-fault/

See sub-sec # 1 (asterisk at the end) for this quote:

"(*The rifle must have a mil-spec gas port and a barrel of 14.5” or 16” with carbine gas system. On mid-length gas system guns, use the Sprinco standard CAR-15 spring. This spring and heavy buffer do not consistently work in Rock River Arms rifles, from my experience.)"

Knowing what we all know about RRA's gaping gas port sizes, I think it's logical to infer that their chambers tend to be tight. Somebody please correct me if I'm coming to an incorrect conclusion.

[DemonRat]

I'd suspect that port to be somewhere in the .080'' range, and as high as .093'' from what I know.
Is this size true for most M4's or are there to many variances out there. As there are company's that make AR's. I was just curious about this as I have never really paid attention to the gas port size.

[steelonsteel]

I don't intened to keep it - I had been talking about doing this length and a friend said I could borrow an upper he has had for a little while. If I like it, I'll buy my own, probably a bravo company.

He's been running it on his lower with just a carbine buffer :eek: on a pistol lower :eek::eek:

I have a carbine buffer, though I think that's probably a bad idea, and an H. I think I may go ahead and buy an H2, and then just try all three and see how it runs on them all - it will be interesting to find out anyways, and spare buffer won't be a bad thing!

[Tweak]

I would shoot it with that and see what it does.


Or pull the FSB and mic the port. Life's too short to play what ifs.

[steelonsteel]

I haven't pulled this exact one off, but several sources indiacte it should be .080 to .081

I ordered an H2 from bravo company, will try that and see if it locks back on an empty mag, and if not then I'll experiment and see what happens from there. Or at least that's my plan at this point, unless someone sees/knows something I don't.

[Iraqgunz]

Who said? Maybe you are taking something out of context? It matters if you are trying to get the proper buffer to keep it running- especially in an SBR.


Hold on.... you're telling me gas port diameter matters?

All this time reading M4C and The Chart, I thought it wasn't something we were supposed to worry our pretty heads over.

[Belmont31R]

Hold on.... you're telling me gas port diameter matters?

All this time reading M4C and The Chart, I thought it wasn't something we were supposed to worry our pretty heads over.





Im not an SME by any stretch but my personal theory is that a factory gun should be able to run smoothly on a a carbine or H1. Running an H2 or H3 with reliable operation would mean to me the gun is running with way too large of a gas port. Keep in mind I mostly use Colt recoil springs with some BCM ones tossed in that Ive gotten from time to time.


If you can run an H3, and still getting reliable lock backs with 223 ammunition that gun is in a world of hurt sarcastically speaking.

[BufordTJustice]

Im not an SME by any stretch but my personal theory is that a factory gun should be able to run smoothly on a a carbine or H1. Running an H2 or H3 with reliable operation would mean to me the gun is running with way too large of a gas port. Keep in mind I mostly use Colt recoil springs with some BCM ones tossed in that Ive gotten from time to time.


If you can run an H3, and still getting reliable lock backs with 223 ammunition that gun is in a world of hurt sarcastically speaking.

Ordinarily speaking, I agree with you.

But, I have found that there are some parameters that can change the equation on a properly ported rifle.

2 examples.

1) My BCM 14.5" middy will run a 7.3oz SS-body buffer (from heavybuffers.net) AND a Blue springco spring or Tubbs flatwire spring as long as I use a NiB BCG. When I go back to a phosphated BCG, I'm left with an H3 on a std rate spring (that's only 100% on NATO ammo). I find myself settling on the H2 w/ the Tubbs for smoothness purposes despite being able to go much heavier. The H2 w/ the Tubbs is the smoothest combo on the return stroke during recoil (BCG going back into battery) and my micro jiggles the least when using this setup.

2) The NGA X7 uses a Noveske 14.5"-middy afghan barrel (with a conservative GP size) and it runs either a springco Blue or Red with an H2. However, it also has a coated BCG (proprietary ceramic coating).

Outside of these two examples, I generally agree with you.

[Clint]

So I have an SBR upper, and Ive been loaned for a week or so a differant upper to try. Here's the rub - it's an 11.5" upper from Rock River Arms. Yeah, I know - not really top of the chart - but for the price [read; free] I'll play with it.

Now, if I understand correctly, RRA tends to run their gas ports larger than mi-spec? Or perhaps I'm wrong on that?

If that is so, then theoretically, I should be using a heavier buffer - like say an H2... correct?

I have access to carbine and H buffers. But I'm wondering if shouldn't go ahead and buy the H2 for this, as I don't want to damage anything [since it's not really mine].

If I run too light of a buffer things will slam around and could potentially amage something right? or is the only drawback higher recoil?


If the upper is just to play around with, most likely you don't NEED to do anything.

The upper will likely still operate, but will have high cycle speed.

This tends to reduce reliability at every phase of the operating cycle.

My general advise is that an H2 is good to have around and is my first choice in a CAR length RE.

As pointed out by Todd long ago, the H2 has roughly the same moving mass as the original rifle buffer that the system was designed with and is generally sufficient to eliminate bolt bounce.

[Magic_Salad0892]

Is this size true for most M4's or are there to many variances out there. As there are company's that make AR's. I was just curious about this as I have never really paid attention to the gas port size.

Milspec carbine gas is .062'' for a 14.5'' gun.

A Colt Commando should have .071, or so.

RRA uses anywhere from .080-.093''...

Also, Iraqgunz:

Every time you make that analogy, you use a different porn actress name:

How much ****ing porn do you watch, dude?...

[Iraqgunz]

Porn is very popular in Iraq in a camp with ZERO females and no contact with the outside world.

Plus she is old school porn which means it's really big.


Milspec carbine gas is .062'' for a 14.5'' gun.

A Colt Commando should have .071, or so.

RRA uses anywhere from .080-.093''...

Also, Iraqgunz:

Every time you make that analogy, you use a different porn actress name:

How much ****ing porn do you watch, dude?...

[BufordTJustice]

Porn is very popular in Iraq in a camp with ZERO females and no contact with the outside world.

Plus she is old school porn which means it's really big.

I'd have to imagine that even if females WERE present, it wouldn't make a damn bit of difference, since they're prolly not gonna be the kind you would want to warm ur boom-stick for any length of time. ;)

[Magic_Salad0892]

Porn is very popular in Iraq in a camp with ZERO females and no contact with the outside world.

Plus she is old school porn which means it's really big.

She still does movies, dude.

You guys must get really bored over there.