Can someone explain AR buffer weights to me?

[kymasabe]

So, I have a couple of springs and buffers that came with build kits, but was just reading that if I want to get the "twang" out of the gun when firing, that I should switch to a flat-wire recoil spring. Then, I got wondering if I should replace the buffer as well, vaguely remembering something about an H2 being a better choice, but the info I found online was confusing so...
Is there a need to upgrade a recoil spring and/or buffer?
And if I replace the buffer, which should I install (for carbine length? for mid-length?)
My goal I guess would be a slightly slower cycle rate, and a little gentler on the gun, but without compromising reliability.

[marine6680]

The "twang"

I hear that flat springs reduce it... It has never bothered me personally.

It's caused by ossilation in the spring, a pressure wave, after the bolt in locked in battery. Flat springs apparently do not ossolate as much or just don't make as much noise.


Buffer weights...

There is not hard rule, but there are some guidelines. You are looking to get optimal ejection from the rifle. Between 3 and 4:30 o'clock... Basically straight to the side or slightly to the rear.

The unmarked "carbine" buffer was phased out in military rifles, it only really sticks around due to it's cheapness. It could be useful in some builds, where pressures are weak or short, like very short dwell time setups. Like a 10" barrel with a carbine gas system.

The H buffer is the new standard now, and a good starting point for most builds.

I use the H2 buffer a lot, even in a midlength system, I find they work fine.

An H3 is good for rifles that are very over gassed. Some rifles with carbine length gas on a 16" barrel can be pretty over gassed. An H3 can work here. I have seen advice that on such a setup, a heavier buffer spring and H3 is a good way to go... I would avoid a heavier spring unless needed, as the forward force is increased, and can lead to long term issues... But it could be useful on a rifle that may see use in a harsh environment.


The difference between the different types in how much they weigh. The weights are easy to look up online.

Internally the difference comes in what the buffer weights are made from... Inside the buffer are three weights... They are cylinders of metal separated by rubber spacers. The goal is for the buffer to act like a dead blow hammer and not allow bounce. The weights shift around to accomplish that goal.

A "carbine" buffer has it's three weights made of steel.

An H (or H1) has two steel weights and one tungsten weight.

H2 two tungsten... H3 has all three tungsten.


As far as reliability... It's an easy test.

Buy a few boxes of cheap 223 ammo, maybe a box of Tula or other steel cased ammo... These are the weakest ammo you will likely use.

You want to use a variety to be sure the test is reliable.

If you never shoot anything but 5.56 spec ammo, then use that instead, but if it cycles the weakest 223, it will cycle anything, and will cycle 5.56 reliably even in harsh conditions.

To test reliability... Load two rounds into a magazine. Fire one round, the rifle should cycle fully and feed the next round. Fire the second round. The rifle should cycle and lock back properly. If it does not lock back, or hangs up on the follower rather than the bolt stop... Then you are short stroking.

Repeat this test several times each with every ammo type you brought... If it works correctly, and the ejection pattern is correct, then you are good.

You should also check that the rifle cycles with the magazine loaded to full capacity, as spring pressure against the bottom of the bolt will slow it down... More rounds in the mag means more pressure on the bolt.

If it doesn't cycle properly, or if the ejection is very far rearward, then the buffer is too heavy... If the ejection is a bit forward still, the buffer is too light.


I personally like to see 223 eject around 4 o'clock, as that usually puts 5.56 spec ammo ejecting around 3 o'clock. So I get good reliability with all ammo.

For a duty rifle, a bolt speed on the faster side of correct/in spec, means better reliability in harsh conditions.

For a range gun or competition rifle, slower is good. Makes for less recoil. If you want the lowest recoil, an adjustable gas block, with low power buffer spring, lightweight BCG, and reloads on the weak side... Makes recoil very light.

That is the basics... If you need any more info or specifics, ask away.

[kymasabe]

Perfect. Thank you!!

[bfoosh006]

BTW... a little grease ( on the buffer spring ) will also tame some of the twang.

And if your buffer tube is anything other than smooth inside... that will make a "racket" as well.... I hone mine smooth. helps with my personal traits I prefer in my AR's

[TrueBlue711]

I want to get the "twang" out of the gun when firing

I hear the Geissele Super 42 Braided Wire Buffer Spring is the best buffer and buffer spring out in the market to get rid of that "twang". I just ordered one, so I can't say for myself. But the reviews are almost all 5 star saying it gets rid of it completely.