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Posted: 6/14/2009 1:05:15 PM EST
I`m gonna buy a BCM Mil-Spec Buffer Tube Kit and noticed they give you options on your buffer weight, I think I have a standard buffer right now on my 16' hbar carbine and it seems to work just fine. I have a tapco t-6 kit right now which is why I aint sure what weight the buffer is. Should I just get the standard weight buffer or upgrade to an H buffer? thanks
Link Posted: 6/14/2009 1:10:01 PM EST
[Last Edit: 6/14/2009 1:11:46 PM EST by CJan_NH]
When you are shooting your rifle and the brass ejects, where does it land relative to your rifle (3 o'clock etc)?

Posted Via AR15.Com Mobile
Link Posted: 6/14/2009 1:18:39 PM EST
Since I would like to know the answer to this as well... My brass usually goes forward. Like 1-2 o'clock.
Link Posted: 6/14/2009 1:21:16 PM EST
I think mine usually goes about 4 or maybe 5 o'clock. Between 3 and 5 o'clock for sure.
Link Posted: 6/14/2009 1:49:57 PM EST
0330hrs. for me.
Link Posted: 6/14/2009 1:54:08 PM EST
I've always wanted to know what the different buffers did for ejection.

Link Posted: 6/14/2009 2:03:42 PM EST
Link Posted: 6/14/2009 2:24:33 PM EST
Does somebody know an answer for us? thanks
Link Posted: 6/14/2009 2:29:05 PM EST
what time is it now?
Link Posted: 6/14/2009 3:26:02 PM EST
I think i recall reading that if your brass is ejecting/landing around 3-4 o'clock, you have the right weight buffer. If your brass is landing around 5-6 o'clock, go with a lighter buffer; 1-2 o'clock, go with a heavier bufffer
Link Posted: 6/14/2009 3:38:36 PM EST
At some point in the life of your carbine, yes an H, H2, H3 and Extra strong action spring will keep your carbine running.

Ive been able to extend the life of a 10.5 by upping the buffer weight and spring strength as the upper wore. What happens is that as you get a higher round count, you start to get gas port erosion. This allows more gas into the system, and leads to first higher cyclic rates, and then to sheared bolt lugs. By being smart with the parts replacement and changing you buffer and spring you can extend the life of an upper way beyond that which the military considers an upper shot out. This is taking into account that you will still have throat erosion and a loss in accuracy.

Link Posted: 6/14/2009 3:52:35 PM EST
I just built my AR and have only put about 120 rounds through it so I guess I`ll get a BCM Mil-Spec Buffer Tube Kit with a standard weight buffer. Thanks for the help.
Link Posted: 6/14/2009 4:22:42 PM EST
[Last Edit: 6/14/2009 4:51:15 PM EST by CJan_NH]
Sorry for the delay guys-I got called away unexpectedly with a situation at the office.

A heavier buffer slows down the cyclic rate of the bolt and carrier. Many manufacturers build their rifles to be slightly over gassed for reliability. This over gassing will cycle the bolt and carrier faster, which will result in brass being ejected more toward the 12 o'clock position. An under gassed carbine will typically show weak extraction, with brass being ejected more toward 6 o'clock (or it will short stroke and not cycle at all). Ideally, brass should eject between 1 and 3 o'clock. Over gassing to the extreme induces more felt recoil, and increased wear and tear on the rifle. Due to variances in ammunition, it's better to be slightly over gassed than under gassed to maintain reliability.

You can slow down an over gassed carbine with a heavier buffer to get your ejection pattern between the desired 1 and 3 o'clock position. Like everything else in life however, it's possible to go too far. If you go too far you can induce weak extraction, or even short stroking. If your rifle is demonstrating weak extraction, an extractor spring and/or o-ring upgrade would be the proper initial course of action.

It needs to be said that the buffer is only one component in an overall system that includes the ejector, extractor, and extractor spring.

Hope this helps

Edited for clarity.
Link Posted: 6/14/2009 4:46:21 PM EST
Originally Posted By blasterrider88:
I`m gonna buy a BCM Mil-Spec Buffer Tube Kit and noticed they give you options on your buffer weight, I think I have a standard buffer right now on my 16' hbar carbine and it seems to work just fine. I have a tapco t-6 kit right now which is why I aint sure what weight the buffer is. Should I just get the standard weight buffer or upgrade to an H buffer? thanks

My carbines/M4`s
will run on
H buffer
9mm RRA buffer

Never any problems with M4 14.5 and a 9mm buffer
even with 223 loads
Link Posted: 6/14/2009 4:50:25 PM EST
[Last Edit: 6/14/2009 4:52:53 PM EST by FMJ]

Bushmaster lower
VLTOR Tele with H buffer
LMT 14.5 upper

ejects brass at 1

LMT D2000 14.5 M4
9mm buffer

Ejects brass at 5

Both run 100% so far

All I care about is being on target faster
and 0 jams

so Im sticking with the 9mm buffer / D2000 M4 over 2000RDS fired

Link Posted: 6/14/2009 7:02:56 PM EST
Simple answer is yes it will if the carbine has a three shot burst or a full auto happy switch.
Will it make a semi auto carbine more reliable?
Maybe, maybe not.
It won't make a semi auto carbine any less reliable.
Link Posted: 6/14/2009 7:06:51 PM EST
I ordered the BCM Mil-Spec Buffer Tube Kit and just went with the standard buffer. I can always "upgrade" later if needed. Thanks for the information and help.
Link Posted: 6/14/2009 7:09:03 PM EST
mine ejects at 7-8.... lefty
Link Posted: 6/14/2009 7:47:57 PM EST
Originally Posted By AzArAk:
mine ejects at 7-8.... lefty


Others have pretty much covered it. It all depends on how your own rifle/carbine is cycling now. Those ejection patterns listed above help identify this.

Link Posted: 6/14/2009 8:02:06 PM EST
Yes the point of a heavier buffer is to slow the unlocking of the bolt wich carbines do faster and more violently than a 20" gas system increasing parts wear and stress making the carbine extract at peak chamber pressure.20" rifles are in the original design parameters so chamber pressure is zero on extraction.A heavier buffer increases dwell time so more gas and chamber pressure are bled off before extraction wich ideally is the goal for a smoother,cleaner less violent running system.

I went 9mm buffer and enhanced LMT carrier wich has a hump in front protecting the bolt better and a third vent hole to eject more gas and also the cam pin tract cut differently than a regular carrier to increase dwell time to a point almost that of the full size rifle.My brass ejects at 3 to near 4 oclock getting thrown about 7 to 8 feet.I use and x power spring and black insert on the extractor so with that I know chamber resistance on the ejected empty is minimal at best using this combo of parts.The 9mm buffer gives a little heavier weight than a full size buffer.I pretty much function wise have my carbine functioning like a full size gas system.

The great thing is ive had wolf be under powered to the point that I have had trouble from time to time in a full size rifle. The benefit of the carbine with these enhancements is you get rifle benefits with the shorter gas system that so far has never malfunctioned with underpowered ammo..finaly a benefit of the shorter system.
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