AR rifle buffer questions

[tdbru]

i've never torn a rifle buffer apart (driven out the roll pin) to see what i hear shaking around in there. has anyone? are they steel BBs? if anyone has opened one of the rifle buffers up to see what is inside please let me know. i'm curious. i don't want to tear mine apart because, if i understand it correctly, once a roll pin is used, you have to replace it to keep it tight in the assembly. you can't reuse it and expect it to be tight. and i'm not sure where i could get a new buffer roll pin as the rifle buffers are usually sold assembled. and i haven't noticed anyone selling new rifle buffer roll pins.
thanks,
-tdbru

[A5BLASTER]

You can buy them.

It's not BB's in there. It's a few small weights.

You can Google ar15 buffer or ar15 buffer weights and there should be a pic come up somewheres that shows a rifle and carbine buffer taken apart.

[tdbru]

thanks A5B. i can find the weights for the Carbine buffer on display no problem. haven't yet found a picture of a rifle length buffer disassembled. hence the question. i'll keep looking.
-tdbru

[A5BLASTER]

thanks A5B. i can find the weights for the Carbine buffer on display no problem. haven't yet found a picture of a rifle length buffer disassembled. hence the question. i'll keep looking.
-tdbru

It's the same weights just more of them.

[Cowdog]

RifleBuff1.jpgRifleBuff2.jpg

Rubber disks in between the weights. A lot of what looks like dry graphite power in for lubrication.

[FRB6.5]

OP may find this of interest, a buffer kit with nine weights and spare ends and pins:

https://www.kakindustry.com/shockwave/ar15-buffer-system

[PNWTargets]

Do you need to change the buffer weight?

[Sturmgewehr]

Depends...

I'd like other opinions on this video.

[Cheyenne Bodie]

Small Arms Solutions is the best channel on YT in my opinion. Chris is always dropping serious info and direction.

[Klem]

tdbru,

I wouldn't imagine a loose buffer roll pin will be a problem given the number of times gas block pins are tapped out and re-used. I have never heard of drifting roll pins or heard of a buffer pin drifting out.

Has anyone else?

[Lastrites]

I reuse them and haven't heard of a pin drifting out to be a real problem, but is something to check if odd short stroke issues are popping up. My sons 5.56 rifle recently had an odd irregular stroke issue out of the blue, I removed the spring & buffer to find the rubber bumper split in half right at the roll pin channel with the end of floating around in the receiver extension. That was a first for me, odd one on a fairly new rifle.

[PNWTargets]

I was asking about the buffer weight to see if that is why you wanted to take it apart. I have experience with different buffer weights and different springs if you need help. Just message me.

[tdbru]

thanks guys. i was curious how a heavier (i.e.tungsten weighted) buffer would slow down the point at which the whole mass moved far enough back to expose the end of the gas tube. theory i am wondering about is, if the reciprocating mass went up enough, the gas pressure at time of gas tube exposure to the action interior would be way lower due to the longer time for more recip mass to move enough to expose the end of the gas tube. hopefully resulting is less carbon deposit in the action. i.e. a cleaner action. since my setup is a semi anyway, lengthening the cycle time is a moot point. it still is ready to go again way before i am. can't really add mass to the BCG unless they make Tungsten BCGs, but i've not seen any yet. so the buffer may be the only way to add mass to the reciprocating assembly. has anyone tried this experiment yet? gone with a very heavy buffer? did it make the action cleaner?
thanks,
-tdbru

[A5BLASTER]

thanks guys. i was curious how a heavier (i.e.tungsten weighted) buffer would slow down the point at which the whole mass moved far enough back to expose the end of the gas tube. theory i am wondering about is, if the reciprocating mass went up enough, the gas pressure at time of gas tube exposure to the action interior would be way lower due to the longer time for more recip mass to move enough to expose the end of the gas tube. hopefully resulting is less carbon deposit in the action. i.e. a cleaner action. since my setup is a semi anyway, lengthening the cycle time is a moot point. it still is ready to go again way before i am. can't really add mass to the BCG unless they make Tungsten BCGs, but i've not seen any yet. so the buffer may be the only way to add mass to the reciprocating assembly. has anyone tried this experiment yet? gone with a very heavy buffer? did it make the action cleaner?
thanks,
-tdbru

Your going backwards with going heavy really. The only real way to reduce carbon in the action is to limit the gas that goes down the gas tube.

More gas in, more crude in the action. Less gas in, less crude in the action.

What will happen by going heavy is you will slow down your unlock time and smooth out the recoil impolse, but it's not going to keep the action cleaner. What you will we is one weight man this is awesome, let's try 2 weights. Man that's even better, let's try 3 weights and then the gun probably won't run anymore from being undergassed.

To break it down more. If you have a regular gas block installed. Your going to get all the gas down the gas tube that the gas port and pressure can make. As you add weight you will slow the action and smooth out the felt recoil. Till you get to heavy and run into under pressure problems because your system is too heavy to cycle with the gas.

If you have a adjustable gas block, you can choke down the gas needed to run standard weight setups and by doing that properly time the system and reduce the gas and crude being blown into the action.

You can go to the far side and go adjustable gas plus lowmass bcg and lowmass buffer and reduced buffer spring rate. That will allow you too cut the gas down even more and then also cut down on the crude getting into the action.

But then you also very much reduce the operating window that your rifle will work, because everything is so light weight it will reach the point of being to dirty to work much much faster. Even though your action is cleaner then it would be if running more gas for the same amount of shots.

All the things I just posted will work to accomplish a certain improvement. But adding weight to the system to slow down a non adjustable gas setup will never make it run cleaner.

Hope this helps sir.

[tdbru]

Thank you A5B! i find this very interesting. if i understand the functioning of the Stoner DI gas system, the gas goes down the tube, through the gas key, and into the chamber created by the bcg and the back end of the bolt. once the bcg moves enough to, supposedly, cycle the action, the bolt piston rings uncover the gas vents in the side of bcg as it moves back and the bolt doesn't (yet). so the gas in the chamber is vented out the ejection port. as the bcg comes back far enough, the gas key comes off the end of the gas tube. if at that time, there is still gas pressure in the tube i assume it will get dumped into the action. however, please correct my understanding here, if it is in error, if there is no gas pressure in the gas tube when the bcg backs up far enough for the gas key to uncover the end of the gas tube, no more carbon should be dumped into the action. right? so how can that happen? one way i can see that happening is if the reciprocating mass is high enough that the bullet is long gone out the end of the barrel and all the residual gas pressure behind the bullet and in the tube has relieved itself as is follows the bullet out the muzzle. another way it appears is the oft mentioned adjustable gas block. if the recip mass were infinite, for sure, the gas pressure would be 0 relative to the atmosphere before the bcg moved enough to expose the end of the gas tube. and if the recip mass is "standard" weight, then i assume there's still quite a bit of gas pressure in the tube when the bcg backs up enough to uncover the gas tube. but how much recip mass is required to allow the residual pressure in the gas tube to reach 0 relative before the gas key uncovers the gas tube?? do anyone know Stoner's design equations. mass and spring constant, acceleration, energy loss to unlock the bolt and extract a case, etc? it seems to me that if you throttle the gas, you can indeed reach a point where there was not enough pressure in the chamber to accelerate the bcg enough to complete the cycle. but, if you increase the mass, your bcg accelerates slower, but carries more momentum due to the increase in mass. so might still cycle the action.

just as an experiment, if i find a tungsten buffer, solid, without the hollow, that would weigh quite a bit. it would be interesting to me to see if my rifle would still cycle at all with an increase in recip mass to the max possible. and if it would, shoot 100 rounds and inspect the action for carbon deposits. then do the same thing with the standard issue rifle buffer. and see if there is a difference at all in the amount of carbon in the action. i probably wouldn't want to ask, however, what a solid Tungsten buffer would run.

any mechanical engineers here? or any that would want to chime in?

thanks,
-tdbru