A Tale of the Fives. A5 that is.

[Iraqgunz]

As most many M4C members know, I am a big fan of the Vltor A5 receiver extension/buffer system. I got my first one sometime in 2010 as I recall and every single AR that I have has a a version of an A5.

The Vltor A5 can be had in a 6 position or 7 position version.

Not too long ago, BCM started making it's own version the Vltor A5 which has some design changes and uses 8 positions.

Now more recently Magpul Industries which is no stranger to the stock game has started to produce a 6 position MILSPEC standard extension and their version of the A5 which has 10 positions.

One can only guess that this is being done due to meet the demand of the A5 which seems to have picked up steam over the last couple of years and often times listed as "out of stock" in many places.

The Magpul version which I received recently is nicely made. The dry film lubricant applied inside the tube is evident. The installation into the receiver was as tight and solid as any other quality receiver extension I have installed.

Top to bottom. Vltor, BCM and Magpul A5 versions.





Vltor 6 position extension. Stock fully collapsed.



BCM 8 position extension. Stock fully collapsed.



Magpul 10 position extension. Stock fully collapsed.

[Kdubya]

Frankly, I'm a little late to the A5 RE and Buffer System craze. I've now spent a decent amount of time researching it in recent months, and it does have me intrigued. The David Tubb video comparing springs was very Bill Geissele-esq. For one, they both have a storyteller voice, and I could probably listen to them talk about technical data for hours on end. On a more practical note, David's video provided some tangible data to support the rationale of switching out a part that may not be actually causing any problems.

Now, for the topic at hand, isn't the "magic" of the A5 less about the tube and more about the action spring and buffer? I understand the RE is the vessel that makes the magic of those items possible, and the additional positions fill a demand. But, if it weren't for the spring and buffer, and the only difference were the additional positions, would people be going as crazy over the A5 system? Assuming that the demand would not be as high if the sole benefit was additional stock positions, I'd like to focus on the spring and buffer. Are the three systems you mentioned all that distinguishable from each other in the spring & buffer regard? Admittedly, I haven't looked into the BCM or Magpul that much, but a cursory look yields the following comparisons.

VLTOR A5 - Proprietary Spring and Proprietary Buffers that are only compatible with the VLTOR A5.

BCM - Compatible only with a Rifle Action Spring and VLTOR Buffer(s)

Magpul - Bring your own Springs and Buffers. Standard carbine hardware? No problem. A5 proprietary equipment? That'll be fine too.

Assuming the above assessment of each is accurate...

Can the VLTOR really only be run with their own proprietary components? What is it that makes those components incompatible with standard carbine tubes, especially the buffer?

Will the BCM run with a VLTOR Action Spring? The fact that they advise a Rifle Spring with a VLTOR A5 Buffer indicates the answer to my question above is that the VLTOR Buffers can be used in conjunction with traditional springs.

Is the Magpul the most versatile? It will apparently work with just about any combination of springs and buffers. That doesn't mean each will run perfectly, but it seems to allow the end user the greatest amount of latitude. But, if run with a standard carbine spring and buffer, is the main advantage of the system lost?

Ultimately, if each is used in its intended configuration, is there any discernible difference in performance? If so, which would you give the nod to?

[Iraqgunz]

Yes, you are missing alot. All of the A5-ish tubes use a rifle spring and all of them must use an A5 buffer. The A5 buffer is patented and cannot be copied unless you do not copy it exactly which is what heavybuffers.com has done.

The real "proprietary" part of the system is the buffer.

[Col_Crocs]

Is it just me or does the magpul sit the stock a little further out at fully collapsed?
Have you ever used the heavy buffers version? How does it compare?

[ESK]

One must remember that there are two types of rifle springs, Commercial and Milspec. Commercial is weaker than Milspec. The Vltor A5 system was developed to work only with the Milspec Spring. Vltor and BCM only sell Milspec springs.

The only reason BCM made their Receiver Extension is to offer a locking position for the full collapse of their stock and stocks like the Vltor IMod. Plus BCMs tube was made to be slightly lighter than the others. Vltor, BCM and Magpul receiver extensions will also allow the total collapse of longer stocks like the Magpul ACS and the Vltor EMod. Vltor offers two AR receiver extensions, one for short stocks (IMod) and one for long stocks (EMod). The only difference of the two tubes in the length of the locking track.

All A5 receiver extensions have the same internal depth to the Armalite AR10 receiver extension. The bores depth is 0.710 deeper than the standard M4 receiver extension.

[BFS]

Im still waiting for someone to come out with a A2 length tube with a channel on the bottom and carbine type attachment method.

Like an A5 only another bit longer-

so that we can use collapsible stocks with standard A2 buffers.

Nobody would even notice the extra length, who even runs their stocks collapsed all the way down?

[Falar]

I understand what the benefits of the A5 system are but wonder if you can't get the same effect with putting a heavier buffer and stronger spring into a standard carbine receiver extension?

I just got a 6920OEM2 and a 6.8 build setup and wanted to give it a shot but the buffers were out of stock everywhere and I didn't want to continue waiting on the UBR2 to come out so just used regular UBRs with H3s and springco blue springs. Since the goal of the A5 is to control the bolt better with a heavier buffer and stronger spring it seems to me like a different way to accomplish the same thing.

[Col_Crocs]

I understand what the benefits of the A5 system are but wonder if you can't get the same effect with putting a heavier buffer and stronger spring into a standard carbine receiver extension?

I just got a 6920OEM2 and a 6.8 build setup and wanted to give it a shot but the buffers were out of stock everywhere and I didn't want to continue waiting on the UBR2 to come out so just used regular UBRs with H3s and springco blue springs. Since the goal of the A5 is to control the bolt better with a heavier buffer and stronger spring it seems to me like a different way to accomplish the same thing.

It's not just the heavy buffer, it's the consistency of the rifle spring.

[Falar]

It's not just the heavy buffer, it's the consistency of the rifle spring.

So a stronger carbine length spring is not the equal of the rifle length spring? I thought a sprinco blue/red should be sufficient to prevent any bolt bounce as well as delay extraction a bit.

[Clint]

So a stronger carbine length spring is not the equal of the rifle length spring? I thought a sprinco blue/red should be sufficient to prevent any bolt bounce as well as delay extraction a bit.

A spring does neither.

Buffer construction counteracts/damps bolt bounce.

Overall bolt system mass slows rearward acceleration and therefore delays extraction.