Small Arms Solutions video: "The Buffer - Theory and when to Use What Buffer"

[MountainRaven]

I recently came across this video and found it to be interesting.

To wit, the proper choice of buffer weight is apparently largely based on how heavy the barrel is. So the LE6920 and M4 have H buffers because of the government contour barrels they have, while M4A1s with the SOCOM contour barrel have H2s because of how much heavier the SOCOM barrel is (and the H2 was originally developed for Colt's piston-operated guns). And then the H3 was developed for the super-heavy barreled Colt IAR.

So... is the premise correct? If so, is it not foolish to chase after different buffer weights for rifles, should one not choose the buffer weight based on the barrel contour rather than a perception of being overgassed or undergassed?

[vicious_cb]

That is completely wrong...

[MountainRaven]

That is completely wrong...

Did I misunderstand him or is he wrong?

[scottryan]

The heavier the gun or barrel, the worse the bolt bounce is, as the gun has more interia to resist the BCG from going into battery.

[vicious_cb]

Did I misunderstand him or is he wrong?

You should NOT be choosing buffer weight based on barrel profile. Buffer weight should be based on gas system + gas port size aka how much gas drive is accelerating your bolt carrier. By increasing the reciprocating you are lowering the carrier velocity and allowing more time for feeding and extraction.

Is what he is saying true, yes BUT its almost like he read some historical engineers note on what the buffer was originally designed to do which was act like a dead blow hammer to keep the bolt carrier from bouncing back. As most of us know, the buffer plays a far more important role than that.

[Clint]

Yes, the reciprocating mass and gas drive should be matched.

Our approach is to select the A5H2 buffer first and adjust gas drive to achieve proper function.

This works well for any possible configuration.

Rifle or CAR H2 buffers are acceptable alternative baselines.

You should NOT be choosing buffer weight based on barrel profile. Buffer weight should be based on gas system + gas port size aka how much gas drive is accelerating your bolt carrier. By increasing the reciprocating you are lowering the carrier velocity and allowing more time for feeding and extraction.

[Artiz]

You should NOT be choosing buffer weight based on barrel profile. Buffer weight should be based on gas system + gas port size aka how much gas drive is accelerating your bolt carrier. By increasing the reciprocating you are lowering the carrier velocity and allowing more time for feeding and extraction.

Is what he is saying true, yes BUT its almost like he read some historical engineers note on what the buffer was originally designed to do which was act like a dead blow hammer to keep the bolt carrier from bouncing back. As most of us know, the buffer plays a far more important role than that.

He worked at Colt, and read every Engineering Change Order dating back to the 60's up to very recently (2005 I think). He knows what he's talking about.

The thing is, what he is saying relates to Colt and military use, not necessarily civilian use. Colt issues the M4 with H buffers for a reason. The military wants it's rifle to function 100% no matter how fouled, dirty or dry the gun is and how cold the temperature is. They're not gonna put too heavy of a buffer in there and risk the gun not cycling in ALL conditions possible. The AR15 is already a borderline system.

The free-moving buffer weights were implemented to kill the bolt carrier bounce that created failures to fire on full auto. The bigger the barrel mass, the more bounce the bolt carrier is going to experience, the heavier the buffer should be to kill the bounce. Simple physics.

The buffer weight use in the civilian world is gonna vary wildly based on personnal preferences and the fact that too many manufacturers build barrels with too much variation in gas port size, and people run the whole spectrum of ammo from low-ass power garbage to very hot 5.56.


He isn't saying "you absolutely have to use that buffer with that gun or imma break yo legs fool".

[Iraqgunz]

The Army currently uses H2 buffers in their carbines as they are being converted over to SOCOM profiles, if they haven't done so already. Gas port sizes in both barrels is the same. Put an H2 buffer in a 6920 and it will run all day long.

He worked at Colt, and read every Engineering Change Order dating back to the 60's up to very recently (2005 I think). He knows what he's talking about.

The thing is, what he is saying relates to Colt and military use, not necessarily civilian use. Colt issues the M4 with H buffers for a reason. The military wants it's rifle to function 100% no matter how fouled, dirty or dry the gun is and how cold the temperature is. They're not gonna put too heavy of a buffer in there and risk the gun not cycling in ALL conditions possible. The AR15 is already a borderline system.

The free-moving buffer weights were implemented to kill the bolt carrier bounce that created failures to fire on full auto. The bigger the barrel mass, the more bounce the bolt carrier is going to experience, the heavier the buffer should be to kill the bounce. Simple physics.

The buffer weight use in the civilian world is gonna vary wildly based on personnal preferences and the fact that too many manufacturers build barrels with too much variation in gas port size, and people run the whole spectrum of ammo from low-ass power garbage to very hot 5.56.


He isn't saying "you absolutely have to use that buffer with that gun or imma break yo legs fool".

[MountainRaven]

You should NOT be choosing buffer weight based on barrel profile. Buffer weight should be based on gas system + gas port size aka how much gas drive is accelerating your bolt carrier. By increasing the reciprocating you are lowering the carrier velocity and allowing more time for feeding and extraction.

Is what he is saying true, yes BUT its almost like he read some historical engineers note on what the buffer was originally designed to do which was act like a dead blow hammer to keep the bolt carrier from bouncing back. As most of us know, the buffer plays a far more important role than that.

That had been my understanding. The link between buffer weight and barrel contour was completely new to me, but the way it was laid out in the video made sense and made me think I knew less than I thought I did (which wasn't much to begin with).

[vicious_cb]

He worked at Colt, and read every Engineering Change Order dating back to the 60's up to very recently (2005 I think). He knows what he's talking about.

The thing is, what he is saying relates to Colt and military use, not necessarily civilian use. Colt issues the M4 with H buffers for a reason. The military wants it's rifle to function 100% no matter how fouled, dirty or dry the gun is and how cold the temperature is. They're not gonna put too heavy of a buffer in there and risk the gun not cycling in ALL conditions possible. The AR15 is already a borderline system.

The free-moving buffer weights were implemented to kill the bolt carrier bounce that created failures to fire on full auto. The bigger the barrel mass, the more bounce the bolt carrier is going to experience, the heavier the buffer should be to kill the bounce. Simple physics.

The buffer weight use in the civilian world is gonna vary wildly based on personnal preferences and the fact that too many manufacturers build barrels with too much variation in gas port size, and people run the whole spectrum of ammo from low-ass power garbage to very hot 5.56.


He isn't saying "you absolutely have to use that buffer with that gun or imma break yo legs fool".

Thats perfectly fine if he's repeating whatever reason the engineers wrote down as a historical anecdote but that isnt reality. I know for a #fact that there are savvy SF guys out there who will tune their buffer weight specifically to drop the the cyclic rate on their 416s suppressed and unsuppressed. Its also a #fact that there guys out there that had to scrounge H6 buffers because the H1's in their M4s didnt play well with M855A1. If thats not a military application I dont know what is.