Theoretical advantage of A5 buffer system?

[Disciple]

Don't suppose you know what would be the ideal flavor of A5 (has to be H0 or H1...cause anything heavier won't work) for an upper that won't run anything heavier than an H1 carbine and milspec carbine spring?

It's not that simple! I'm still trying to wrap my head around this observation.

When using the LMT e-carrier, Vltor A5 system, tubbs flat wire AR10 spring, and an SLR gas block, using several verified 5.56 NATO chambers, A5H0 buffer did not permit a smaller gas block "port" adjustment than the A5H4 buffer. In fact, on my suppressed 11.5" Sionics RGP and BRT 16" OPTIMUM intermediate gas barrel with the above setup the A5H4 permitted a smaller gas port setting on the gas block than the A5H0 or any of the other buffer weights (I tried all of them on all of my uppers, suppressed and unsuppressed). Yes, you read that right.

The A5H4 permitted me to run less gas than the A5H0.

I appreciate the few posts above showing lots of experimentation, but there is more going on here. Period.

[Jmacken37]

I’m an admitted A5 fanboy. I’m currently liking the ‘amphibian’ setup using a kynshot RB5007 hydraulic buffer (endorsed by no less than Kyle Lamb), an A5 length tube, and Tubbs flat wire 300BLK or 556 flat wire spring. Very smooth setup.

https://www.kyntec.com/product/rb500...pplication-12/

[JediGuy]

I’m an admitted A5 fanboy. I’m currently liking the ‘amphibian’ setup using a kynshot RB5007 hydraulic buffer (endorsed by no less than Kyle Lamb), an A5 length tube, and Tubbs flat wire 300BLK or 556 flat wire spring. Very smooth setup.

https://www.kyntec.com/product/rb500...pplication-12/

I wonder if running a regular rifle spring vs the flatwire would equal the results.
The additional cost of the buffer has kept me away from trying it out. The A5 system by itself is already very good.

[Clint]

To put it simply, the overall gas impulse goes toward two things.

1) accelerating the moving mass
2) overcoming friction forces during extraction

In general, adding mass reduces acceleration and peak speed of the moving mass.


HOWEVER, those extraction related friction forces decrease with time as bore pressure and temperature drop.

IF increased mass delays extraction enough to reduce that friction, the saved energy is used to accelerate the mass to normal speeds.

It's not that simple! I'm still trying to wrap my head around this observation.

[Clint]

To get started, you can build a new lower using the longer receiver extension.

A spacer (such as the Colt 9mm spacer), rifle spring and CAR type buffer can be used after verifying proper travel.

This provides some benefit from the rifle spring and allows a future upgrade path the an actual A5 buffer in the future.

I wonder if running a regular rifle spring vs the flatwire would equal the results.
The additional cost of the buffer has kept me away from trying it out. The A5 system by itself is already very good.

[JediGuy]

I should clarify, I do use the A5H2 buffer. My comment was about combining the Kynshot buffer with the A5 tube and rifle spring.

[BufordTJustice]

To put it simply, the overall gas impulse goes toward two things.

1) accelerating the moving mass
2) overcoming friction forces during extraction

In general, adding mass reduces acceleration and peak speed of the moving mass.


HOWEVER, those extraction related friction forces decrease with time as bore pressure and temperature drop.

IF increased mass delays extraction enough to reduce that friction, the saved energy is used to accelerate the mass to normal speeds.

Clint, you nailed it.

If the extraction is delayed until case obturation has largely subsided, there is more energy left in the overall energy budget to contribute to accelerating the carrier/buffer mass to the rear.

I’ve actually experimented with a custom 9.5oz A5 stainless buffer and it functioned just as well as the A5H2 and A5H4 through your OPTIMUM 16” Intermediate Gas barrel (which is already properly gassed), THROUGH an SLR Ti AGB with about 50% restriction.... at the exact same setting.

That is nearly a doubling of buffer mass. And it STILL locked back on empty with no shoulder purchase on XM193 and my sh*tty busted aluminum mag with dented feed lips that I use for just such a test (lock back). That was 62F in the indoor range that day.

As you said, there’s plenty of energy in the system to gas the gun properly AND have more than enough margin for operation.
The fact that your barrels come with properly cut chambers and leads/throats sure does help accomplish that.


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