Buffer Education

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Spectrum726
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Buffer Education

Post by Spectrum726 »

Hi Guys,
New to this site, but would like to know the different usages and reasons for the different buffers. I understand they are id'ed by weight, is that correct? Then there are H1, H2 and H3, what would these different ones be used for? Are there different buffer springs too or are they pretty much the same.

Thank you!
hardcase
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Re: Buffer Education

Post by hardcase »

My understanding on buffers is it has to do with recoil. Using the appropriate buffer for the load will keep you from beating up your gun with different calibers. Pistol gas vs rifle gas makes a difference too as do suppressors. Also if you shoot subs you will need an appropriate buffer. My 9 mm AR is recoil, not gas operated and needs a heavy buffer.

To really get fine tuned some get an adjustable gas block too.

Different springs help with noise.
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doubloon
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Re: Buffer Education

Post by doubloon »

Buffer weight generally corresponds to the length of the gas tube and is generally recommended/required to be matched for fully open gas ports. Loads and suppressors aside.

An adjustable gas block can be used to compensate for buffer weight, load and suppressor variances to a large degree but don't come without their own headaches.

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John A.
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Re: Buffer Education

Post by John A. »

Without getting into a lot of tech speak, here's what you need to know.

The ar15 uses gas to push the bolt back.

Some guns have more gas, which would require a heavier buffer to counter that.

You can also use a slightly heavier buffer than needed to keep the bolt closed slightly longer. Or vice/versa.

The even shorter answer, if you use the wrong buffer, your gun may not cycle correctly, or at all.
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ECCO Machine
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Re: Buffer Education

Post by ECCO Machine »

John A. wrote: Some guns have more gas, which would require a heavier buffer to counter that.

You can also use a slightly heavier buffer than needed to keep the bolt closed slightly longer. Or vice/versa.

The even shorter answer, if you use the wrong buffer, your gun may not cycle correctly, or at all.
Eh, yes and no. An ounce or two in the buffer makes little difference (if any) in most cases with semi auto guns. If changing the buffer takes it from functioning to not, or not functioning to running, the thing is on the ragged edge of cycling properly to begin with. An AR that's built right will run just fine with anything from a completely empty buffer to H3 or even HSS. I've personally tested this with different gas systems and barrel lengths. You might notice a small change in recoil impulse going from carbine to H3, but if the gun is right, it will run with any buffer.

The buffer is designed to mitigate bolt bounce, which is why the weights are free to move fore and aft within it. On a semi auto firearm, bolt bounce really isn't an issue; you could stick something in the buffer to stop the weights from moving and the gun would still run. Where it matters is in full auto. The buffer weights are at the rear of the buffer when it's going forward, and they slam forward into the front of the buffer when the buffer stops with the bolt carrier, preventing it from rebounding. If you have a full auto that is dropping the hammer without ignition, chances are a heavier buffer will fix it. My shop M16 will run fine with a carbine buffer unsuppressed, but the higher bolt velocity with a can causes too much bounce if I don't run an H3. In semi-auto, the gun will run with either buffer, suppressed or not.

On that note, bolt bounce is also the reason closed bolt semi autos are difficult to convert to full auto. Even if you know that you can't just "file a firing pin" or "file a sear" as the myths go, and even if you know enough to realize that yanking the disconnector will make it a single shot, so you built an auto sear and properly timed it, it's still highly unlikely to run with a stock bolt. It might double or triple from time to time, but it will be erratic, usually one shot followed by a dead trigger. The bolt needs a sliding weight, properly calibrated, to stop the bolt bounce and allow the hammer or striker to fall with the bolt fully in battery. It's far easier to make a semi auto run reliably than a machine gun. Everything is moving faster, causing a number of issues not present or problematic in semi auto operation.
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John A.
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Re: Buffer Education

Post by John A. »

While I was painting with a very broad brush, you added a lot to the reply that I didn't go into for the sake of brevity.

One example, my 300 integrally suppressed blackout.

The powders that I use require a very light (1 oz) buffer and lightweight tubbs/superior shooting spring, but in fairness, they're not powders that are normally used in blackouts.

But, they are much more quiet than any commercial ammo out there and with the way I have it set up, is just as reliable as any other AR15. If you didn't know that it had a light buffer and spring in it and been tuned to what and how I shoot, you would never know it if you just happened to shoot it.

While I agree that a simple change in buffer tension/weight normally doesn't make a huge amount of difference, there are times when it's better when the results show it to work.

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Re: Buffer Education

Post by cdhknives »

Lots and lots of opinions of buffers, most of them right to some degree. From my experience, I notice a substantial reduction in full open slap (buffer bottoms out the recoil spring) with a heavy buffer when shooting full power suppressed. A good running AR will usually go to 'overgassed' when a suppressor is attached. The heavy buffers help mitigate this as well. As stated above, adjustable gas blocks are another approach to this problem.
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