Can someone comment on or point me to a comparison of the differences in the AAC rate reducing buffer and the MGI rate reducing buffer?

Quoted: Can someone comment on or point me to a comparison of the differences in the AAC rate reducing buffer and the MGI rate reducing buffer?

Well, they work quite differently.

On the MGI unit, when the buffer hits the rear of the buffer tube the internals are set into motion against the bolt carrier, etc.  Acts like a deadblow hammer and helps to reduce recoil and ROF.

On the AAC unit, when the buffer hits the rear the free sliding weights compress the buffer spring further and hold the buffer to the rear of the buffer tube just a little longer.  The AAC also comes with a weaker buffer spring to use, but it's really not good for .223/5.56mm so I don't use it.  It's too weak to strip .223/5.56mm rounds off the magazine, does great for 9mm though.

AAC used to make a heavier "tungsten" version of their buffer which is tested here:

www.c3junkie.com/m16/access/buffers.html

They do not offer it today.   The version they have today is much lighter and not as good at reducing ROF.

If you don't include the weakened buffer spring they rank about like this for reducing ROF:

1.  MGI RRB / AAC old buffer - right about equal, edge goes to MGI RRB.
2.  AAC new buffer

As far as reducing recoil, here are my subjective opinions in .223/5.56mm SEMI:

AAC old buffer - never tested
AAC new buffer - very slight, almost non-existant reduction in recoil compared to my H buffer.  Seems it's more about reducing ROF.
MGI RRB - definetly a difference but the .223 doesn't exactly recoil all that hard to begin with.  I'd say is consistently recoils a bit softer and muzzle movement is more controllable.  In FA the difference is much more pronounced (or so I've been told by many).  Remember the MGI unit has been used with success with .458SOCOM and .50 Beowulf, it's THAT strong.  The higher your recoil or ROF, the more reduction you will see from the MGI RRB.

I have some other information saved at work I think, I'll update this post when I get there if there is anything useful to add.  If you want I can take pics of both buffers.

i have the mgi buffer in my .50 beowulf and it made a good amount of difference. made it bearable to shoot.


i would say that it made my .50 shoot more like a .308

Quoted: Hey! You guys are doing a great job! I didn't even have to add anything! Trying to get a Group Buy started on the EE. Really alot of interest in the buffer now on Arfcom.

im in for another one

I just wanted to add:

If your rifle/carbine is getting JUST BARELY enough gas to cycle the action 100% as it is, the extra weight of the buffer (or any heavy buffer, H3, 9mm, AAC, MGI or otherwise) could prove to be too much weight to cycle properly 100% of the time.  It's just simple logic, the more weight & resistance you have the more force you'll need to move it.

It's not at all the fault of the design of any of those buffers, just the added weight.

When an upper is BRAND NEW, that's where the greatest potential for the heavier buffer's not to work lies.  If the upper is getting just enough gas to cycle as new, use it and break it in (less parts resistance, more gas coming, etc.) and usually it will start working with heavy buffers just fine.

Quoted: Hey! You guys are doing a great job! I didn't even have to add anything! Trying to get a Group Buy started on the EE. Really alot of interest in the buffer now on Arfcom.

Have one for the .458 SOCOM.  I want two more.

Dave S

bump, for new question, what about the mgi vrs the enidine ar-resistor hydraulic one? Anyone have both?

Any links to this product?  Any idea what kind of long-term reliability/round counts it will hold up to?

Quoted: Tested them both in the same gun with the same buffer spring and the Enidine was noticably better at keeping the muzzle down in semi auto.  I have not compared them on full-auto. Also, if you shot the gun without a solid hold, like you held the gun with by the pistol grip and fanned the trigger, the MGI would not always cycle back far enough to pick up the next round using M193.  It always failed to pick up the next round with Wolf.  The Enidine hydraulic buffer would always cycle, but would not always lock back on the empty magazine.  I believe the issue lies in the MGI's 7.0 oz weight versus the Enidine's 4.1 oz weight.  With the testing I have done on semi auto, it appears to be a superior product at a superior price.   Brett

Interesting.  I had heard of hydraulic buffers, and also that the Colt version was "problematic".  Is this product an improvement?  In what way?  

Next question.  The way a buffer acts while in motion is important, hence hydraulics/springs/shifting masses, etc.  But another important characteristic is inertia.  And inertia seems particularly important with respect to carbine gas systems.  I don't see how the 4.1 oz buffer will help here.(?)

Sam

Extractor lift due to bolt rotation during unlocking has been proven to be a myth (a wide-spread and long standing one!) by the fine folks at Picatinny Arsenal.  Heavier buffers help extraction because the added mass requires more force to cycle the firearm.  This delays unlocking and extraction, allows pressures to drop and the case to shrink away from the chamber wall -- easing extraction.  Heat also plays a roll because as the barrel heats up the case takes longer to shrink away from the chamber walls, heavier buffers slow the ROF which helps to control heat to some extent.

Extractor lift actually occurs during initial reward translation of the bolt, residual chamber pressure holds the casing against the bolt face until the extractor can return to its original position.

IM me your e-mail, I'd be happy to send you the documents I am referencing from Picatinny if you want them.  My other reference is here:

www.armalite.com/library/techNotes/tnote48.htm

Many are quick to just boost extractor tension to "fix" their problems.  It's often the first thing they try, it works so they leave it at that.  I tend to try everything I can to make it work as best it can with a standard extractor spring, this usually means tweaking the gas system, weight of the parts of the action or other tricks.  THEN add the extra power extractor spring on top of it to attain the highest margins of reliability I can out of a particular upper.

I'm a bit confused, wyv3rn states extractor lift during bolt rotation is a myth, but the documents he quotes states it actually does occur, during rearward movement of the bolt - so extractor lift (which the o rings/ defender help with) does occur, the difference in your opinions is when? When I pull the bolt to the rear on my ar with the charging handle, is seems to me the bolt moves rearward first about 1/4" , then pulls on the bolt to turn and unlock it. I don't think during the inital rearward bolt carrier movenent there would be any stress on the extractor as the bolt is still locked, only during and right after unlocking when the bolt face is moving rearward would pressure be put on the extractor to hold the round...

Got it, wyv3rn's view is the extractor issue is not caused by a "bounce" condition but simply by the carbine gas system issues - high chamber pressure, short gas systems, heat, etc, all which try to pull out the cartridge before it is ready..

I guess we can all agree the bolt can move to quickly to the rear / unlock to quickly and pull the extractor lip off the cartridge, either caused by "extractor bounce "or just a short gas system, dirty or tight chamber, hot loads, etc. In any case the hydraulic buffer should ease this condition by slowing down the process and giving it more time to unlock.  

I field stripped a saw a while back and thought I remembered a hydraulic buffer inside....


edited after reading below post -

Quoted: Extractor lift actually occurs during initial reward translation of the bolt, residual chamber pressure holds the casing against the bolt face until the extractor can return to its original position.

I do not believe the Armalite article says when it occurs, just that it does.  But even if it did I wouldn't be suprised if they got it wrong too.  We all did.  Like I said.. long standing and wide spread.

Quoted: When I pull the bolt to the rear on my ar with the charging handle, is seems to me the bolt moves rearward first about 1/4 , then pulls on the bolt to turn and unlock it. I don't think during the inital rearward movenent there would be any stress on the extractor as the bolt is still locked, only during and right after unlocking when the bolt face is moving rearward would pressure be put on the extractor to hold the round...

I promise you your bolt does not get a running start at the barrel extention lugs, then rotates or you wouldn't have a bolt left.  The 1/4 (inch I assume) you are speaking of could be the distance the CH travels before it hits on the carrier key.

The bolt unlocks, then there reward movement of the bolt.  The case is held to the bolt face by residual pressures, the only pressure put on the extractor to "hold the round" is that given by the extractor spring.

My carrier seems to move to the rear about 1/8 - 1/4" BEFORE the bolt begins to rotate - it is the gas from the gas tube into the carrier, which then  begins moving rearward and then begins the bolt rotation to unlock the bolt. Doesn't the rearward carrier movement mechanically cause the twist of the bolt to unlock it? Or are you saying the gas in the barrel unlocks the bolt before the carrier moves or that the gas from the gas tube goes into the bolt and unlocks the lugs?

Quoted: My carrier seems to move to the rear about 1/8 - 1/4" BEFORE the bolt begins to rotate

Yes the carrier moves rearward for a small distance before the bolt begins unlocking.  This is due to the way the cam pin slot is cut in the carrier.  The bolt itself does not move rearward until it is fully unlocked.

- it is the gas from the gas tube into the carrier, which then  begins moving rearward and then begins the bolt rotation to unlock the bolt. Doesn't the rearward carrier movement mechanically cause the twist of the bolt to unlock it? Or are you saying the gas in the barrel unlocks the bolt before the carrier moves or that the gas from the gas tube goes into the bolt and unlocks the lugs?

As the bullet travels past the gas port, gas is forced into it, through the gas tube and into the carrier key, into the sealed chamber aft of the bolt inside the carrier.  The gas pressure forces the carrier rearward, as it does so it impinges on the cam pin which unlocks the bolt.  Once unlocking is complete the bolt begins its initial travel rearward where the extractor looses its grip momentarily and residual gas pressures hold the fired casing to the bolt face until the extractor returns to its position over the case rim.  Bolt assembly continues traveling rearward and yadda yadda yadda you know where it goes from there.

Thanks - that makes sense - guess I hijacked my own buffer comparison question a bit