Over a CAR buffer, if you have an adjustable gas block?
An “H” or “H2” buffer will cycle slower and less violently. I know what you mean, ‘shouldn’t changing the gas block setting do this?’… It does change how much gas force pushes on the BCG. The buffer weight changes the speed that the BCG reacts with. Heavier buffer is smoother/slower.
I was wondering the same, but I already bought an H buffer and a new spring to go with it, it is from BCM so it shipped instantly 
so I should be able to tell you next weekend, if I am lucky enough to go shooting again.
But using H buffer will require more gas, which seems to defeat the purpose of the lower gas for lower recoil. Unless I’m missing some thing. Why do competition shooters all use low mass stuff of h buffer is softer?
Low mass carriers and buffers are most suitable for race guns.
The advantage they have, with reduced gas drive, is less movement off target after the shot.
This is generally at the expense of reliability in all conditions.
For general purpose carbines, I like the H2, A5 and rifle buffers.
They all have approximately the same amount of moving weight inside.
This is important to eliminate bolt bounce upon chambering.
The action spring needs to deliver enough energy to strip and chamber a round, even when hot and dirty.
The heavier weight makes this less sensitive to friction and keeps the final carrier speed lower.
The slower forward acceleration also means the bolt spends more time behind the catch, increasing reliability of stripping a new round even if the magazine is a little slow lifting it.
Finally, the gas drive.
The gas drive should only be strong enough to cycle the action reliably with a weak hold while hot and dirty.
Too much gas creates high carrier acceleration and speed.
This causes earlier unlocking and extraction before the case is cooled off and contracted, which makes it more difficult.
So for a more reliable softer shooting gun, one should use an H buffer with just enough gas to lock back instead if a carbine?
My LE6920 came with an H buffer.
Softer shooting isn’t always more reliable.
The AR BCG, buffer & action spring must be balanced for proper speed and weight to ensure the action has the right amount of momentum for reliable extraction, ejection and feed with the proper ammunition. Heavier reciprocating mass means it accelerates slower and a possible loss of momentum resulting in a loss of reliability.
If the reciprocating mass is too heavy for the action spring and has insufficient damping, there will be bolt bounce. If there is too much acceleration and insufficient damping, there will be bolt bounce.
There is a reason why a minimum and maximum allowable rate of fire is specified for optimal performance of the AR.
You will have to try your AR with different weight buffers with a variety of ammo to see which works best, or if you plan to stay with a single type of ammo, which buffer works best with that.
My carbine runs good with a carbine buffer but feels too slow with an H buffer. However, I will have to shoot and compare the two more to verify this
I have an adjustable gas block , I can tune the gas to the gun instead of tunning the buffer to the gas.
I agree.
Looking at what the competition shooters run is a bad idea for a real world application in my opinion.
For a more reliable gun, one should not use and adjustable gas block. Unless its a race gun an not a tool to stake your life on.
Not true with the adjustable blocks that have the ability to lock the setting down…such as the SYRAC and (I’m assuming) the new Wilson Combat Adj. GB…and of course the Switchblock.
Clint, good post!
Just for clarification, if you have an adjustable block that can tune the gas for any particular ammo/buffer/spring combo, it would be better for reliability to have a heavier buffer than a lighter buffer through a wider range of conditions, correct?
Ex. I have the SYRAC block tuned to a LMT Enhanced Carrier, Carbine buffer, and GI Carbine Spring. It is very soft shooting.
Would this setup be more reliable if tuned to a heavier buffer? And if so, which buffer would be best (H-H3)?
The Syrac Ord adjust able has a detent and is just as reliable.