View Full Version : Rifle Buffer with Tungsten Weight(s)?
Dionysusigma
02-08-17, 22:34
Would there be any reason or advantage to popping open a rifle-size buffer and installing a tungsten weight (or two, or three)?
To be more specific, the rest of the directly related components in question are a BCM midlength 16" upper with a BCM Gunfighter Comp, rifle-length receiver extension, standard rifle spring, and standard rifle buffer, and the ammo used 90% of the time is M193. I haven't had any issues whatsoever, but since it's my favorite rifle I'm wondering if it would help with longevity of parts or an even smoother recoil impulse.
echo5whiskey
02-08-17, 22:56
I'm going to wait for the engineers/more experienced guys to give you a definite, but I'd guess it would have to do with how heavy you make it. I'm curious, to find out though.
The std rifle buffer weighs 5.2 oz. For comparison the A5-H2 weighs 5.33 and would probably be the choice for 90% of us running the A5. If all you shoot is 193 you could probably get away with adding 1 or 2 tungsten weights but I doubt you could tell feel difference in a blind test.
A spring change may be more effective for what you are attempting to accomplish.
Tubbs or SpringCo
Tungsten weights are possible, but a more practical way to add weight is to replace the long aluminum spacer with 2 steel weights and rubber discs.
This brings the total weight up to ~6.15 oz
We call it the the R7 buffer and it seems to work well.
I would suggest what Clint mentions above, easy and economical to try out for the OP's combination.
Reducing the action cyclic rate with additional mass can help durability, just don't push it out of the reliability range for the selected combo.
Another option is to remove the internal aluminum spacer and reduce the spacer length to a little less than a standard internal weight length. That reduced spacer with an added steel weight can have more internal travel. Add in a Vltor A5 spring preloaded buffer pad with the spring relieved steel weight, with the additional A5 travel, you have an excellent baseline buffer that can accept more tungsten mass substituting steel mass if required.
This is what i have done to a rifle with a BCM 16" mid length barrel and it works well
Tungsten weights are possible, but a more practical way to add weight is to replace the long aluminum spacer with 2 steel weights and rubber discs.
This brings the total weight up to ~6.15 oz
We call it the the R7 buffer and it seems to work well.
I've done this with a rifle buffer, swapped the spacer with two steel weights, I prefer it, runs great.
BufordTJustice
02-18-17, 13:28
Tungsten weights are possible, but a more practical way to add weight is to replace the long aluminum spacer with 2 steel weights and rubber discs.
This brings the total weight up to ~6.15 oz
We call it the the R7 buffer and it seems to work well.
Bingo. Used it for several builds on friends' rifles with great success.
Dionysusigma
02-18-17, 18:13
What would happen, say, if one replaced all the steel weights with tungsten (essentially making an H5 or even H7)? Would it run like an undergassed carbine with an H3 and PMC Bronze (frequent failures to feed)?
How does changing the buffer weight affect the recoil impulse? If it slows the carrier down enough, would it end up being something like the SureFire Long Stroke carrier system (https://www.m4carbine.net/showthread.php?184697-Long-stroke-SureFire-Carrier) or the Ultimax 100 Constant Recoil system (https://en.wikipedia.org/wiki/Ultimax_100)? Is there even enough "room" in the AR operating system to allow for something like that?
BufordTJustice
02-18-17, 18:58
What would happen, say, if one replaced all the steel weights with tungsten (essentially making an H5 or even H7)? Would it run like an undergassed carbine with an H3 and PMC Bronze (frequent failures to feed)?
How does changing the buffer weight affect the recoil impulse? If it slows the carrier down enough, would it end up being something like the SureFire Long Stroke carrier system (https://www.m4carbine.net/showthread.php?184697-Long-stroke-SureFire-Carrier) or the Ultimax 100 Constant Recoil system (https://en.wikipedia.org/wiki/Ultimax_100)? Is there even enough "room" in the AR operating system to allow for something like that?
That would be far too heavy. It would basically make it a 13oz buffer. Too much.
To answer your second set of questions, there isn't enough room for that in the current AR15 platform.
Dionysusigma
02-19-17, 07:52
So a max cyclic rate of 120rpm isn't feasible, then? :(
:p
I'm more of a fan of gassing the gun right and forcing the gun to run with the correct/standard buffer. Pappabear and I are in the middle of doing this to 3 or 4 10.5" SBRs using insertable gas ports. It seems that every booger brained manufacturer of 10.5" barrels sees it appropriate to put an .080 +/- port on these barrels. :blink:
Dionysusigma
02-19-17, 10:14
It seems that every booger brained manufacturer of 10.5" barrels sees it appropriate to put an .080 +/- port on these barrels. :blink:
Because nobody would ever run them suppressed, right? :rolleyes:
Is there an engineering table somewhere that correlates dwell time, port size, buffer weight, and gas pressure?
Because nobody would ever run them suppressed, right? :rolleyes:
Exactly. They're pretty over gassed un-suppressed... forget adding the can.
Is there an engineering table somewhere that correlates dwell time, port size, buffer weight, and gas pressure?
Not that I know of. When it comes to 14.5 middy and 10.5 carbine, I know the desired ports by heart.
Running a heavier weight buffer does not change the momentum, you are simply changing the duration in which the reciprocating mass cycles and the "perceived felt recoil changes" I'll explain more in detail in a review im going to post next week. If your goal is for wear and tear I would suggest an adjustable gas block. cheers
Dionysusigma
05-14-17, 20:06
So, the best solution offered (based on others' implementation) is to remove the aluminum spacer, and install two steel weights and rubber discs. How many rubber pieces are needed/recommended? I pulled my rifle buffer apart tonight and after measuring the spacer at 1.25", it seems that (plus the steel weights) only one rubber disc is required... but I'd like to make sure before I order.
The std rifle buffer weighs 5.2 oz. For comparison the A5-H2 weighs 5.33 and would probably be the choice for 90% of us running the A5. If all you shoot is 193 you could probably get away with adding 1 or 2 tungsten weights but I doubt you could tell feel difference in a blind test.
I use an A5-H3 and a Sprinco Green, but I don't run any weak ammo.
Tungsten weights are possible, but a more practical way to add weight is to replace the long aluminum spacer with 2 steel weights and rubber discs.
This brings the total weight up to ~6.15 oz
We call it the the R7 buffer and it seems to work well.
Is somebody selling a kit like this? BTW - I found that the Tubbs flat wire made a real difference in a rifle length buffer for a carbine gas 16" barrel.
Heavy Buffers carries an 11-ounce XH buffer for rifles. It'll work with M193.
The XH buffer or tungsten insert carrier weight system help to keep the system locked longer. It makes the rifle operate smoother as the system literally takes longer to unlock and cycle. It stresses brass less as it'll have cooled and not be expanded (obturated) against the chamber walls.
Dionysusigma
05-14-17, 23:28
I'm trying not to spend $125 on a buffer, though my "RH7 Concept" in post #10 would run a little over $90 after shipping... :jester:
Dionysusigma
05-16-17, 05:15
Out of curiosity, what was the original intent behind the aluminum spacer in rifle-length buffers? Compatibility with underpowered ammo?
You can build your own 11-ounce XH with Geissele or other tungsten inserts.
Dionysusigma
06-02-17, 08:17
Well, two extra tungsten weights and rubber spacers are coming in from KAK today. Initial plan is to turn an existing H into an H3, and the rifle buffer into an R7. If the H3 is too much, I'll dial it back to an H2 and bump the rifle into an R7H1 of sorts. Ammo for testing will be Federal M193 (which is what I use 95% of the time anyways).
For the record, both buffers at their current weights operate fine in their respective systems.
Out of curiosity, what was the original intent behind the aluminum spacer in rifle-length buffers? Compatibility with underpowered ammo?
The original AR10 used the same rifle length receiver extension and a shorter buffer that contained 6 weights and almost no free space weighing in at 5.4 oz.
When the AR15 was developed from the AR10, they extended the buffer length by 3/4" to shorten the operating stroke, which made room for 7 weights plus a little free space.
They must have determined 7 weights would be too heavy and replaced 2 weights with an aluminum spacer, dropping the weight by an ounce down to 5.15 oz.
The top 2 paragraphs could be expanded into multiple chapters, from the notes I know that I have seen.
Issues, possible solutions, conditions that we possibly cater to.. etc..
Dionysusigma
06-02-17, 22:11
Welp, got the buffers apart and made an R7 (7 steel + rubber spacers) rifle buffer, and an H3 carbine buffer. Of note, the aft bumper on the H buffer had to be drilled and carved out of the body (and yes, I removed the roll pin, same as on the rifle buffer). Bastard was stuck in there almost like it had been glued, but fortunately it had been assembled with the tungsten weight furthest aft so the drill bit didn't harm anything.
Fortunately, KAK sells replacement bumpers, so the standard translucent originally from the rifle buffer went into the H3, and the new, blue, buffer bumper I ordered went into the unconventional R7 to help differentiate it from all the others. As an added precaution, I also stamped the face of both with their new designations: a "3" after the "H" on the carbine buffer face, and "R7" on the modified rifle buffer face.
I'm no Molon, but as soon as I can, I'll hit the range again and post my findings.
Edit: Spring in the carbine system is a BCM-sourced standard carbine spring from late 2012 with ~2,000 rounds, and the spring in the rifle RE is under 1,000 rounds, sourced from Fulton Armory in mid-2016.
Dionysusigma
06-02-17, 22:24
When the AR15 was developed from the AR10, they extended the buffer length by 3/4" to shorten the operating stroke, which made room for 7 weights plus a little free space.
They must have determined 7 weights would be too heavy and replaced 2 weights with an aluminum spacer, dropping the weight by an ounce down to 5.15 oz.
When did the specification for modern M193 publish, compared to the adaptation of the AR operating system in .222 Remington/.224 Springfield/ .222 Special/ etc.? Was the inclusion of an aluminum spacer a relic from that particular development era?
With the recent thread regarding the valuable data on port sizes in this subforum, I don't want to discount things like buffer weights, spring strength, ammo pressures, dwell time, etc. - especially since buffer weights, ammo, receiver extension springs (and by extension buffer systems including the A5) are much easier for an end user to change than the barrel port diameter.
The current rifle buffer came out later than the .222 Remington to .223 Remington change.
What about this buffer? Anyone have experience with this?
https://www.ammoland.com/2014/07/mgis-rate-and-recoil-reducing-buffer-lessens-ar-15-recoil/#axzz4iyVu00Up
After reading this thread I just ordered two steel weights and spacer from KAK to play with my rifle buffer. Ordered a tungsten weight as well just to have.
NYH1.
Swapped my rifle buffer to all steel weights and rubber discs. I also use a Sprinco green spring. Shot it yesterday with my 16" carbine and 20" rifle uppers and it works great.
NYH1.
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