What does everyone recomend for the buffer weight for a Bravo Company Socom 14.5" upper with a pinned flash hider?

I'm in the middle of my build using a BCM 14.5.  I'm planning on a Spikes ST.-T2 as that works well in my Aero 14.5. YMMV

Is that comparable to a h or a h2?

Spike's Tactical T2 has tungsten powder inside and is same weight as H2 buffer.

I have a collection of buffers and I prefer the H3 in my 14.5

I have a BCM 14.5 pinned M4 and use the Spikes. Hasn't let me down so far. It's between the H and H2 in weight.

spikes buffer weight

H2 is the issued buffer in the M4A1 which is what that upper is.

I prefer a heavier buffer(I run A5H4s in most my guns) and I ran a H3 with Wolff XP spring in my M4 upper.

here's a good read on it.

http://www.defensereview.com/the-big-m4-myth-fouling-caused-by-the-direct-impingement-gas-system-makes-the-m4-unreliable/

Bolt bounce is really only a problem in automatic fire and that's what drove the development of the different buffer weights.

For a semiauto, even though it is present, it isn't nearly as much of an issue except possibly as the carbine becomes very, very fouled.

The different buffer weights are to address the differing amounts of bolt bounce in carbine barrels of varying weights.  All else being equal, the heavier the barrel, the more pronounced is the bolt bounce.


For a 14.5" - 16" heavy / SOCOM-style barrel: H2.

For a 14.5 - 16" M4-style or lighter barrel or shorter barrel (like the Colt Commando): H.

The H3 is something of an odd duck.  It seems like for every person who swears by the H3 there's another who swears at the H3.  It's probably best not used for 5.56, but for 6.8 SPC, etc.

I have a recent production Colt 6520 16" lightweight barrel.  Sprinco suggests their red recoil spring with a H buffer for later production 6920 (16" M4-style) barrels.  It's on order right now.  I'm interested to see how that turns out.

 

Interesting, where did you get the info for buffer weights corresponding to barrel profiles? I have never heard that before. I just started running an H2 in my lightweight 16" middy and am now wondering if I should put the H buffer back in.

Can you expand on this ? Is this just because of an overall mass of the barrel/gun ?

Run whatever you feel comfortable with, my BCM 14.5" middy runs fine with a RRA 5.4oz buffer and a Wolff xtra power spring.

H or H2 are what I normally recommend.

Yes, can please provide some documentation to substantiate these claims, I've never heard this before.

That's what's in my BCM 14.5" carbine (pinned FH).....runs great.



 

I think it was in Black Rifle II.

Yes, the heavy barrel, having greater mass, has more inertia (i.e. resistance to movement) than a lighter barrel does.  Therefore, when the bolt carrier slams into the barrel extension the bolt carrier bounces back more with a heavy barrel than it would with a lighter barrel.

That's my take on it, anyway.

It seems to be backed up by Colt itself (rather emphatically):





The admonition on page 141 makes sense.  Because the carrier is bouncing back more, the sliding weights inside the buffer must be heavier to overcome that greater rearward force and drive the bolt carrier group forward into battery.

"Yes, the heavy barrel, having greater mass, has more inertia (i.e. resistance to movement) than a lighter barrel does. Therefore, when the bolt carrier slams into the barrel extension the bolt carrier bounces back more with a heavy barrel than it would with a lighter barrel.

That's my take on it, anyway. "

This makes sense from a theoretical standpoint, but we're talking about 4 oz of barrel weight difference on a 10lb plus rifle(loaded, mil configured) that is being supported by two hands, a cheek and a shoulder, highly doubt that it make any difference. In the documentation you posted, Colt makes no claim that a heavier barreled weapon is more or less prone to bolt bounce or any reason why a H2 is recommended for them.

"Bolt bounce is really only a problem in automatic fire and that's what drove the development of the different buffer weights.

For a semiauto, even though it is present, it isn't nearly as much of an issue except possibly as the carbine becomes very, very fouled"

can you explain this to us please? Why is bolt bounce more of an issue on semi auto when a weapon becomes very, very fouled?

A lot of what you are saying is in opposite to what I've learned and is in direct opposition of the info in the link I posted above.

I think he's saying a heavier buffer isn't as important in a semi auto rifle as it is in a full auto. The only reason he can see a need for a heavier buffer in a semi auto is as the barrel extension gets more junk in it, a heavier buffer helps to really plow through the gunk and drive the bolt all the way home.

Hello right answer!

Consider this: the barrel is literally the only difference between a Colt 6720 (16" pencil barrel) and a Colt 6721 (16" heavy barrel).  Different twist rate, but same carbine gas system, same material, and every other part of the carbine is literally the same (other than the front sight base and the front sight).  Yet Colt makes the specific point that the H2 buffer is for the 6721 and the like while the others can use the H buffer.  In fact, Colt is emphatic about using a H2 in a heavy barrel carbine.  So what do YOU think is the reason that Colt makes its admonition?
I think it's logical to deduce that it's the difference in the weight of the barrels that alters the weapon's operational characteristics to the point that a different buffer is required for reliable function.
Anecdotally, I was messing around with a M16A1 lower a couple summers ago.  It had a carbine receiver extension and a 14.5" carbine gas heavy barrel.  With a carbine buffer and a H buffer on automatic, I got the stereotypical problem of bolt carrier bounce wherein I couldn't get more than a couple or three rounds off because the hammer struck the firing pin as the bolt carrier was bouncing.  A H2 buffer took care of that.

I trust Colt's knowledge of their own weapon system.

All that said, bolt carrier bounce is really only an issue for automatic weapons and I take Colt's admonition to use a H2 with a heavy barrel carbine to be probably directed mainly at automatic weapons and as a more or less theoretical optimal buffer for that barrel because, other than maybe Jerry Miculek, I don't think it likely that the average person could repeatedly squeeze the trigger on a semiautomatic fast enough to have bolt bounce be an issue.  Unless you go to either extreme of crazy light or crazy heavy, probably any buffer weight would work for a semiauto.  With that in mind, I recommend a H2 for the OP's carbine.

There's nothing in Mike Pannone's article that you posted that has anything to do with bolt carrier bounce.  All he is saying in his article is that he advocates using the heaviest buffer and strongest recoil spring that will allow your rifle to run reliably with the ammunition that you use because he says that it softens the recoil and helps to power through the crud in a neglected carbine.

Yep!

H2 buffer same gas system works fine

Wouldn't it be much more likely that Colt recommends different buffers based on different gas port sizes as opposed to barrel weight?  That would be my first deduction, as opposed to barrel weight, but I am the first to admit I don't know why colt is making that recommendation.

As to the ops original question I would run the heaviest buffer you can with the weakest ammo you use (as is the standard advice).  H2 of you are only shooting 5.56, h if you shoot 223 also.

You posted your opinion as fact and later came back to say, and I quote you, "That's my take on it, anyway". This is a tech forum where people come to learn, not have "your take on it" passed off as facts.

And for The Mike Panone article, his findings directly refute your belief, that was shared with the community as "fact", that a very, very fouled carbine benefits from a heavier buffer.

"2440rds. Problem: chronic short cycling due to excessive fouling caused friction.
At the failure point I replaced the H3 buffer with an H buffer, and the rifle ran reliably again" Mike Panone

I trust Colts knowledge as well, but nowhere did I se them state anything about buffer weight and barrel weight, YOU made that deduction and tried to pass it off as Colt's.

G_MAN,

We are discussing two things here.

The first is bolt carrier bounce.
Colt's armorer's manual exhorts the use of a H2 buffer with a carbine heavy barrel.  When everything else is the same except for barrel weight, but the manufacturer exhorts in bold type and underlining the use of a different buffer, I consider that a clue that there's a link. I am suggesting that Colt recommends the H2 buffer for use with heavy carbine barrels to address increased bolt carrier bounce.  I've seen firsthand a H2 buffer address bolt carrier bounce in a heavy carbine barrel machine gun.  I'm a believer.


On a tertiary topic, fouling came up.
I'm still talking about heavy carbine barrels.  Due to the increased bounce, the spring and buffer must drive the bolt home a second time from a greater distance.  I suggest that for a heavy carbine barrel, since it has to overcome greater bounce, a heavier buffer's greater inertia will achieve that lockup longer on a fouled barrel extension than a lighter buffer, such as a H.

I don't know why you brought up Pannone's article.  He wasn't using a heavy carbine barrel.  He was using a M4 barrel.  In no place do I suggest that a M4 barrel would benefit from a H2 buffer.  I have limited my conversation to the topic at hand, which is heavy carbine barrels and, due to the increased bolt carrier bounce found in in heavy carbine barrels, I say that heavy carbine barrels benefit from a H2.  I also said that bolt carrier bounce is really only a practical factor in automatic fire.  That said, it is also present in semiautomatic fire, and I stand by the assertion that even a semiauto heavy carbine barrel benefits from a H2 buffer, even if it's mostly theoretical and perhaps only comes into practical play when heavily fouled.  In essence, the H2 is to the heavy carbine barrel what the H is to the M4 and lighter barrels: the default good choice.  You've misrepresented my statements as a blanket statement that heavier buffers provide greater reliability in all barrels when fouled.  Not at all.  In fact, I use a H buffer for my non-heavy carbine barrels because buffers, differing mostly in fractions of ounces, can only do so much in the overall scheme.  That said, there's no reason not to optimize (in my case, it's reliability I'm looking for).  As far as saying that a H2 buffer helps to power through crud, I was relating what Pannone said.  The premise of his article is that carbine reliability suffers from typically being under-sprung and under-buffered.... and then he goes on to contradict himself later in his own article before muddling it by saying that the better "shootability" of over-springing and over-buffering the carbine outweighs the slightly reduced reliability.  Frankly, that article (complete with a pertinent typo where he reverses H3 and H during a critical conclusion) is a bit like "Stairway to Heaven": it means whatever you want it to mean.  Posting it did not really increase the knowledge base here.

If you're going to act like a know-it-all hall monitor, you should at least actually read what I've posted.



ETA since I mentioned it earlier in this thread: I got my red Sprinco buffer spring (Sprinco's recommendation for a 16" carbine gas barrel other than early Colt 6920s) in.  I could definitely feel greater resistance when retracting the charging handle.  Test ammunition was Federal XM193 (55 gr 5.56 NATO) and Federal LE223T3 (62 gr .223 Rem).  Buffer was a H buffer (Sprinco's recommendation for a 16" carbine gas barrel).  Barrel was a Colt 16" 6520/6720 barrel, carbine gas.

Using five different known good magazines (NHMTG 20, NHMTG 30, PMAG 20, PMAG 30, and Lancer L5AWM 30) loaded with one round in each, both loads locked the bolt back upon firing.


The XM193 ejected to about 2:30.
The LE223T3 ejected straight out to 3:00, with most of the brass coming to rest at about 3:30ish.

I then loaded the NHMTG 20 for rapid fire.

The XM193 was uneventful.
On the 18th round of the LE223T3, the cartridge failed to feed, with the bolt crushing the side of the case against the barrel extension.

I didn't have time to start troubleshooting it, unfortunately.  The magazine previously was known good with not more than a couple hundred rounds through it.  All the magazines had locked back with one round of LE223T3.  The cases ejecting straight out 3:00 is suggestive to me that maybe .223 Rem is perhaps a little marginal with this setup (red spring and H buffer), but I won't know until I do more testing.

I'm using an ST-T2 buffer and I'm having no problems.

Maybe, but I can't for the life of me think of why Colt would have larger gas ports on their heavy barrels only.  That's the rub: everything else seems to be the same except for weight.

Well why the manual says what you posted (that the H2 is only suitable in the 6721) it is worth noting that the 6721 doesn't ship with an h2 buffer but only an H buffer.

My thought would be that given the twist rate and barrel profile it is more set up for a class of ammunition that warrants the use of a larger gas port.  And if you were going to use stronger ammo you could opt for the heavier buffer.

I'm not convinced that barrel profile plays much of a part in bolt bounce. I've never heard of this before and with all other factors considered, I don't think it makes any difference. I've seen slow motion footage of weapons with lightweight and heavy profile barrels exhibiting bolt bounce, and the bounce was no more pronounced with the heavier barrels than it was with the lighter barrels. These were also in semi-automatic, not full-auto fire.


ETA: I am NOT referring to the Vuurwapen Blog bolt bounce versus buffer weight videos.