AR buffers and springs question

[M1911a1g17]

I was wondering if anyone has insight on this. I know a heavy spring and lighter buffer can perform very well. Is there any sort of benefit to a heavy spring and heavy buffer? Would it allow the bolt to stay closed longer? Or would it just make it harder to tune in the long run?

 

[SKumar]

No benefit. The bolt won't get pushed back enough to pickup the next round upon closing. Next trigger pull will be click. I've had better luck with adjustable gas blocks than fiddling with buffer weights. YMMV

 

[M1911a1g17]

@SKumar what if for example sake let’s say you had enough gas to cycle.

 

[PappyM3]

It depends on what you think of as a heavy spring and buffer. Sprinco “enhanced power” blue springs with H2 buffers are a steadfast combo.

The main consideration is how much gas you have coming back.

 

[LakeTrout]

It will allow for increased dwell time, yes. Whether or not you have cycling issues will depend on the load. You can increase spring rate and buffer weight to increase dwell time and slow the bolt speed down up to a certain point where you lose reliable cycling. And you lose reliable cycling first in the worst conditions. So your rifle may seem to cycle fine after a fresh cleaning and when it’s 70 degrees out, but that same rifle may not cycle fine when it’s a bit dirty and under 30.

You need to decide whether you have a range toy or a legitimate defensive weapon. You’re bringing it closer to its threshold of reliability when you deviate away from tried and true baseline spec.

 

[SKumar]

@SKumar what if for example sake let’s say you had enough gas to cycle.

I guess in theory it would work. But wouldn't more gas keep the bolt open longer?

 

[DarkJoker33]

Honestly, I went out and bought 5 buffers and like 4 or 5 springs all of varying weight and power and dialed it in by feel for the spring and buffer.
I had the gas already adjusted from previous tinkering.
I have to revisit it again (gas) now that I have the buffer and spring dialed in.

 

[LakeTrout]

Honestly, I went out and bought 5 buffers and like 4 or 5 springs all of varying weight and power and dialed it in by feel for the spring and buffer.
I had the gas already adjusted from previous tinkering.
I have to revisit it again (gas) now that I have the buffer and spring dialed in.

You might want to install the buffer and spring that you want to use first and then adjust the gas from there. For example, maybe you want a slightly heavier buffer for increased reliability for a dirty gun, you’d install that buffer and tune your AGB to make sure it’s reliable. Or maybe you want a soft recoiling rifle, you’d install a lighter buffer in that situation and tune your AGB to it to make sure its not over gassed for the lighter buffer.

 

[DarkJoker33]

You might want to install the buffer and spring that you want to use first and then adjust the gas from there. For example, maybe you want a slightly heavier buffer for increased reliability for a dirty gun, you’d install that buffer and tune your AGB to make sure it’s reliable. Or maybe you want a soft recoiling rifle, you’d install a lighter buffer in that situation and tune your AGB to it to make sure its not over gassed for the lighter buffer.

Thanks

 

[M1911a1g17]

@LakeTrout it was just something I was thinking about in a hypothetical way. Obviously any modifications done to a firearm can compromise reliability in a positive or negative way.

 

[PappyM3]

I was wondering if anyone has insight on this. I know a heavy spring and lighter buffer can perform very well. Is there any sort of benefit to a heavy spring and heavy buffer? Would it allow the bolt to stay closed longer? Or would it just make it harder to tune in the long run?

What combination are you thinking about? Personally, I wouldn’t run a heavy spring and light buffer. Light buffers, like light bolt carriers, can result in poor reliability in austere or dirty conditions. Sure, one can tune the gas, but turning down gas doesn’t help reliability/robustness.

Also, what benefits are you reading about using a heavy spring with a light buffer? The heavy spring without a matching buffer will increase bolt closing speed and can increase wear.

It will allow for increased dwell time, yes. Whether or not you have cycling issues will depend on the load. You can increase spring rate and buffer weight to increase dwell time and slow the bolt speed down up to a certain point where you lose reliable cycling. And you lose reliable cycling first in the worst conditions. So your rifle may seem to cycle fine after a fresh cleaning and when it’s 70 degrees out, but that same rifle may not cycle fine when it’s a bit dirty and under 30.

You need to decide whether you have a range toy or a legitimate defensive weapon. You’re bringing it closer to its threshold of reliability when you deviate away from tried and true baseline spec.

The thing with a heavier spring is that it may slow bolt speed… but only on recoil. The heavier spring will cause a faster bolt speed on return.

But 100% with you on reliability concerns when one starts monkeying with edge case recoil setups.

 

[LakeTrout]

@LakeTrout it was just something I was thinking about in a hypothetical way. Obviously any modifications done to a firearm can compromise reliability in a positive or negative way.

Thats cool. I find that the overwhelming majority of ARs are over gassed out of the box. Manufacturers do this so that they can get a good reputation for reliability. Shorter gas systems and larger diameter gas ports. They run any kind of ammo in every condition and that’s great. But they recoil more and are harder on the internal parts. In these cases you can either install an AGB and limit the gas or you can increase buffer weight and spring rate. you’ll get a smoother slower recoil impulse but often times more felt recoil.

In my opinion the best of all worlds, if you’re looking for a balance of reliability and fine tuning for recoil and performance, is probably to allow the correct amount of gas into the system via an AGB or properly sized gas port and a buffer weight and spring rate that are standard for the platform. If you cannot install an AGB and/or you have an out of spec gas port and an overgassed rifle, then increasing buffer weight or spring rate can be a good compromise and won’t decrease reliability for most of us unless you make dramatic increases.

 

[LakeTrout]

The thing with a heavier spring is that it may slow bolt speed… but only on recoil. The heavier spring will cause a faster bolt speed on return.

But 100% with you on reliability concerns when one starts monkeying with edge case recoil setups.

I agree. If an AGB is not an option I’m more in the camp of increase or decrease buffer weight before spring rate. That said, I like flat wire buffer springs like what tubbs has to offer. Very rarely would I want to change spring rate with the exception of using this type of spring. Actually never. I think if you go with a standard spring or a tubbs flat wire spring you should be able to do all your tuning with an AGB and or changing buffer weight. The only tine I’d change spring rate is for lighter loads in a competition gun.

 

[Noreaster13]

I did a little of tinkering with buffers & springs in the past till I tried the A5 buffer tube with the green spring & a5h2 buffer
For 5.56 & 300 hamr it just runs like a clock

 

[M1911a1g17]

What combination are you thinking about? Personally, I wouldn’t run a heavy spring and light buffer. Light buffers, like light bolt carriers, can result in poor reliability in austere or dirty conditions. Sure, one can tune the gas, but turning down gas doesn’t help reliability/robustness.

Also, what benefits are you reading about using a heavy spring with a light buffer? The heavy spring without a matching buffer will increase bolt closing speed and can increase wear.



The thing with a heavier spring is that it may slow bolt speed… but only on recoil. The heavier spring will cause a faster bolt speed on return.

But 100% with you on reliability concerns when one starts monkeying with edge case recoil setups.

Heavier spring and lighter buffer as in using the lightest buffer that runs well. And running that way instead of heavy buffer and lighter spring. The benefit would be a lighter moving weight in the tube.

 

[RoterTeufel]

It's been awhile since I tinkered with my AR, but if I remember correctly I have an H3 buffer with a standard spring on mine.
18" barrel, adjustable gas block...

For me, the extra weight in the buffer also helped keep it a flat shooter w/ less muzzle rise. Add a muzzle device and very little movement/felt recoil.

YMMV

ETA: my 18" barrel is has a mid-length gas system.

 

[RoterTeufel]

Came across my YouTube feed a decent video on different buffer weights and their effects on the gas system:



BTW, I prefer to buy the individual weights and build my own buffer. It's easy enough to do with a punch. The replacement weights are tungsten and stock ones are steel.
View: https://youtu.be/C097NSuqmMM?si=RexkGvjm4mQWzTnF

 

[paul73]

It depends on what you think of as a heavy spring and buffer. Sprinco “enhanced power” blue springs with H2 buffers are a steadfast combo.

The main consideration is how much gas you have coming back.

i was always under impression that all the voodoo with springs and buffer weights are for full auto tuning to accommodate certain loads. for semi we all use it is not relevant.

 

[PappyM3]

i was always under impression that all the voodoo with springs and buffer weights are for full auto tuning to accommodate certain loads. for semi we all use it is not relevant.

It’s more important with full auto, but it’s still relevant with semi.

Most people don’t shoot in austere enough conditions or shoot enough for additional stressors to aggregate into premature parts failure.

But it’s still relevant to people who go light for competitions or people who want something more reliable in austere situations.