Rifle Buffer with Tungsten Weight(s)?

[Dionysusigma]

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...

[Dionysusigma]

Out of curiosity, what was the original intent behind the aluminum spacer in rifle-length buffers? Compatibility with underpowered ammo?

[sinister]

You can build your own 11-ounce XH with Geissele or other tungsten inserts.

[Dionysusigma]

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.

[bfoosh006]

Deleted

[Clint]

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.

[tom12.7]

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]

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]

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.

[tom12.7]

The current rifle buffer came out later than the .222 Remington to .223 Remington change.