Buffer Specifics.

[98Z5V]

This is what buffers do. What a great article.  I bitch endlessly here about buffers, and the right-weighted buffer for what you're trying to shoot.  Damn, we have manufacturers that can't even figure out the basics of a buffer.  This article explains it well.  KEEP IN MIND...  this article is geared for AR15s.  For .308ARs, buffers are a WAY HEAVIER proposition. Don't lose sight of that, when you read this article...

You might not really be "undergassed."  You're probably not "overgassed."  You really need to understand the role that buffer weight plays, before you can make that assessment...

http://www.rifleshootermag.com/gunsmithing/changing-buffer-weight-on-ar15s/

Changing Buffer Weight on AR15s

by David Fortier   |  August 26th, 2016

 

Inside a standard buffer you’ll find three steel weights and three rubber pads. You can change the way your rifle runs by swapping out buffers (from l.): Colt H2 (4.6 ounces); Heavybuffers.com LWRCI’s UCIW (5.5), HSS (6.5) and XH (8.2); a standard buffer (3.0); MGI (7.1); and Spike’s Tactical ST-T2 (4.1).

 

Of all the parts on an AR15, the buffer is perhaps the most insipid. It spends its life hidden in the receiver extension, and when pulled free, it does little to cause excitement. Flat on one end, round in the middle, with a “thingy” on the other end, it’s rather boring to look at. Shake it next to your ear and you’ll hear something rattling about inside. But what does it do, and how can it be hot-rodded to your benefit?

To operate reliably with a diverse array of loads in conditions ranging from extreme heat to extreme cold, even when dirty, requires a careful balancing act. An AR needs to have enough gas tapped off to cycle the action forcefully but not excessively.

If too much gas is tapped off, felt recoil and wear on the mechanism is increased. Too little and the action will not cycle properly, leading to malfunctions, failure to feed or failure of the bolt to lock back on the last round.

Typically, a factory AR carbine will normally be a bit over-gassed to ensure reliable function even in extreme conditions. While being a bit over-gassed aids reliability, it is not always advantageous or even desirable. This is especially true for recreational use or for various types of competition where a lighter-recoiling and smoother-operating cycle is desired. For such use it is possible to tune how the carbine cycles by adjusting the weight of the reciprocating mass: the buffer.

Simply increasing the buffer weight of the reciprocating mass can provide noticeable benefits, including reducing felt recoil and muzzle movement and providing additional mass to aid feeding during the loading cycle. The easiest and most cost-effective way to do this is to simply replace your standard buffer with a heavier model.

If you take apart a standard carbine buffer (which requires only a punch and a hammer: simply drive out the retaining pin and pop off the synthetic pad), you’ll find three steel weights and three rubber pads inside. If you weigh a standard buffer, you’ll find it’s three ounces; the steel weights and the pads account for about 1.9 ounces of that.

Carbine buffers are available in a variety of weights. Colt developed heavier models for certain applications, including the H1 (3.8 ounces), H2 (4.6 ounces) and H3 (5.4 ounces). The H1 uses two steel weights and one tungsten weight, the H2 uses two tungsten and one steel weight while the H3 uses three tungsten weights. If you have a standard buffer and you buy an H3 buffer you can use their weights to build both an H1 and an H2.

Colt’s H series is the most common, but there are also other buffer weights and designs available from the aftermarket. My favorite, which I have used for years, is MGI’s Rate and Recoil Reducing buffer. The MGI buffer features tungsten weights combined with a spring-loaded shock absorber. Its 7.1-ounce weight (more than twice as heavy as a standard buffer) provides a slight delay in bolt unlock timing. This provides extra time for the swelled case to release its grip on the chamber wall, aiding extraction.

The bolt/carrier/buffer’s rearward movement is also slower due to the increased weight. When the MGI buffer strikes the rear of the receiver extension, its mechanical plunger propels the internal tungsten weights forward. These contact the rearward-moving buffer body (internally) and cause a cancellation of the rearward movement just prior to bottoming out. The masses then come to a complete stop, eliminating much of the felt recoil that would otherwise be transmitted to the shooter.

When the recoil spring drives the buffer/carrier/bolt assembly forward, it is also at a slower speed. This provides additional time for the magazine to present the next cartridge. However, it has greater momentum due to the increased weight, which aids feeding. After the bolt locks, the MGI’s internal tungsten weights provide a follow-up hit into the front end of the buffer, eliminating bolt bounce. Felt recoil is noticeably reduced. The only downside is its cost: $165.

Another option is HeavyBuffers.com, which offers a wide variety of AR buffers, 9mm buffers, AR-10 buffers and special designs for Vltor’s A5 system and LWRCI’s UCIW short receiver extension. The HSS features a stainless steel body, tungsten weights and beefy 6.5-ounce weight. The XH model is the heaviest on the market, tipping the scales at 8.5 ounces—almost three times the weight of a standard unit.

Both the HSS and XH are machined from solid 303 stainless steel and sport a smooth, polished finish. They are assembled using tungsten anti-bounce weights, stainless steel roll pins and synthetic pads. They’re nicely made and quite effective. Price is $75 for the HSS and $125 for the XH.

Adding weight to the reciprocating mass is just one possible solution. Another route preferred by competition shooters is to go with a lighter buffer weight, which reduces felt recoil and allows quicker recovery between shots. However, if you do this, you must replace your standard non-adjustable gas block with an adjustable unit because you have to turn down the gas flow with the lighter buffer weight.

One option is Taccom’s LW AR-15 recoil system, which features a Delrin buffer weighing less than one ounce. Price is $23 for a carbine-length buffer and $25 for a rifle-length buffer.

My final thoughts. If it’s a service gun, leave it alone. If it’s over-gassed, and you don’t have an adjustable gas block, adding a heavier buffer can noticeably reduce felt recoil.

If you do have an adjustable gas system, reducing buffer weight can do wonderful things. Don’t be afraid to experiment and have fun with Stoner’s wonderful creation.

Edited July 23, 2018 by 98Z5V

[98Z5V]

I was reminded of this today when I took a new rifle out to shoot/zero an optic.  6.5 Grendel.  What a badass barrel this is turning out to be!  At any rate, it kicked a little more than a typical 5.56 gun, which a Grendel will typically do. No big deal.

When I got back home today, I pulled the buffer. Shiit - I didn't even remember what recoil system I put in this one. Turns out, it was just a regular AR15 buffer in this gun, with a 7" internal-depth receiver extension. Spring was stout - as it should be.  That was an AR15 carbine spring from DSG Arms.  I decided to toss the buffer on the gram-scale.  Came out to 2.95oz. Hmmm, aren't standard AR15 carbine buffers supposed to be 3.0oz?...  Alright, I'm not sweating a few grams here or there, and the gun had some 6.5G recoil to it - it is a hot-rodded cartridge for the small-frame AR.

Lo and behold, what do I have here, that I have no idea what to do with?...  A PSA buffer that came in a .308AR recoil system, and it's marked "H." Let's weigh this thing...  H buffers are supposed to be 3.8 oz. This PSA H buffer came in at 3.85oz...

Okay, for the Grendel, I'll take it, and I'll shoot it, and I'll see what it does.  It'll definitely soften up that recoil "feel" a little.  I'll try an H2 in this Grendel, too, and see what that does.  Bottom line up front (at the end), buffers are WAY more important that people - and manufacturers - think they are.

Thank God, Eugene Stoner figured all that out for the larger-framed rifles, a LONG time ago.  Too bad that manufacturers nowadays ignore his genius...

Edited July 23, 2018 by 98Z5V

[survivalshop]

     I think the author of that article was a 3 gun parts pusher , why are you worried about recoil in a 5.56 Ar any way , you could tell he was a pusher by the $175 Buffer he loved so much , I mean really , recoil in a 22 rifle , please . No doubt he has super light BCG's in his rifles , that increases felt recoil right off the bat . 

 He said it , the Carbine is over gases for a reason .  Components  have a service life & if you want real life functionality , a little recoil is worth it . Far too much ado over the Buffer , IMO.  

Your right 98 , too many manufacturers ( and AR builders )  screw up a very simple formula for AR's , when its all in writing for them to read , just about every where .

[jtallen83]

4 hours ago, survivalshop said:

No doubt he has super light BCG's in his rifles , that increases felt recoil right off the bat . 

Did a low reciprocating mass build in 5.56 a while back and it shoots very soft. I think the key was balancing everything, adjustable gas block, low mass BCG, weaker spring, and no weight in the buffer. Stays nice and flat, even less recoil, and once I got a proper ejector in it reliable with no malfunctions in at least a 1,000 rounds. Catch is all the special parts mean a more expensive build.

[survivalshop]

2 hours ago, jtallen83 said:

Did a low reciprocating mass build in 5.56 a while back and it shoots very soft. I think the key was balancing everything, adjustable gas block, low mass BCG, weaker spring, and no weight in the buffer. Stays nice and flat, even less recoil, and once I got a proper ejector in it reliable with no malfunctions in at least a 1,000 rounds. Catch is all the special parts mean a more expensive build.

Thats just it , ya have to balance everything out , change ammo types or manufacturers much , with out retuning the rifle ?  I like that there are so many different components for the AR's & especially for competition  shooters , but thats a whole different world & if the rifle fails in a Match , no big deal . My mind just doesn't think that way & when someone says ,"I did it to reduce recoil " of a .223 , I just roll my eyes & clear my throat .?

[jtallen83]

I shoot nothing but  XM193 out of it so no adjustment needed. This rifle was built for the wife and pre-teen grandchildren so the recoil reduction does make a difference. Would I pick this rifle for a gun fight, no way but it has been very reliable. The young ones all pick grandma’s rifle when asked what they want to shoot so mission accomplished.