View Full Version : Best BCG/Buffer combo for 16" midlength
Looking to build my own and have a question I can't find a definitive answer to.
I am building a 16" midlength gas AR with collapsable stock and am looking for the best setup.
What's the best BCG/buffer setup for this AR?
In other words If I use an M16 BCG would an H buffer be the heaviest I would use or would it be better to use an AR15 BCG with an H2 buffer?
Or is there a better combination?
lethal dose
10-15-12, 18:55
M16/H is a safe bet.
It really depends on - specific barrel and port size, ammo used, spring used.
My own general rule of thumb with a 16" middy, if you like to use crappy ammo, a carbine buffer would be best. If you use decent ammo or XM193, an H. Carriers I'm not too hung up about - there is very little weight difference between the normal semi carrier and the FA one.
If you like to really tweak, and have the cash to do so, get yourself a range of buffers; things like Sprinco springs also have an impact on the overall equation.
I have a BCM middy (16") and I have an AUTO carrier and run a white Springco spring with a Spikes ST-T2 buffer which is probably between an H1 and H2. I have never had a short stroke or any feeding issue with any ammo. YMMV.
16" BCM middy with FA carrier and 3oz buffer. No problems with Tula, PMC, XM193, or any ammo I've tried.
H
From what I have gleaned from reading here generally for a middy with a standard spring an H buffer and auto BCG are good bets. On my rifle that I am running my BCM middy upper I have a BCM FA BCG, an H buffer bought from them, and standard carbine spring. Not had an issue yet. Have run everything from junk .223, M855, Hornady Steel match, 62gr wolf. Not an issue yet.
It really depends on - specific barrel and port size, ammo used, spring used.
My own general rule of thumb with a 16" middy, if you like to use crappy ammo, a carbine buffer would be best. If you use decent ammo or XM193, an H. Carriers I'm not too hung up about - there is very little weight difference between the normal semi carrier and the FA one.
If you like to really tweak, and have the cash to do so, get yourself a range of buffers; things like Sprinco springs also have an impact on the overall equation.
This. It is a case by case type thing. All AR's with a middy gas system are different. As a general rule, I would go with a BCM BCG and an H buffer, but like to know the barrel manufacturer first.
C4
Buffers don't exist in a vacuum. They are part of an equation, among other variables which include gas system length, gas port size, spring, ammunition and bolt carrier mass.
The best thing to do would be to contact the barrel manufacturer and ask.
Next best thing, accurately measure the gas port and compare it to what is in the gas port size thread and get an idea.
In general, with a 16" mid-length, I would start at a M16 BCG and a H buffer.
Oh I would like to think Mr. SA80Dan for pointing that out. It's very interesting to see the reaction from people in my courses so far when I tell them that every manufacturer does gasports differently and there's no standard except for the established one by Colt. Its also very interesting to see their reaction when you tell them there's no standard for mid lengths.
Thanks everyone. That's the kind of information I'm looking for. I haven't decided on the barrel maker yet. Just have the lower, and have stripped upper on the way.
I didn't know the barrel made that much difference. I had assumed the gas port was basically the same on all mid lengths.
Sounds like I have a good starting point.
Next question. I currently own an LMT Defender. It has a carbine buffer. Would an H buffer be a good upgrade for this rifle or do I need to just leave it alone?
There must be a good reason why LMT uses a carbine buffer in their setup.
Next question. I currently own an LMT Defender. It has a carbine buffer. Would an H buffer be a good upgrade for this rifle or do I need to just leave it alone?
There must be a good reason why LMT uses a carbine buffer in their setup.
My understanding is that with LMT's Defender (16" barrel and carbine length gas system), they sell them with H buffers and carbine buffers, and semi-auto bolt carriers and M16 bolt carriers. I was told (by LMT) that it doesn't really make much of a difference with their guns.
Also, as per LMT, the gas port size is the same for their Defender (16" barrel and carbine gas system), regardless of what bolt carrier or buffer came with the gun new.
That being said, I think a change to an H buffer would be a good idea. But I wouldn't rush to do it. You could probably safely go even heavier. But I wouldn't unless you do it just for experimentation/play.
Joe Mamma
Not sure what the BCG has to do with the situation... just buy a good one.
I'd start with an H buffer, and maybe see if the H2 will work. The H2 carbine system most closely equates to a Rifle buffer system.... and the Rifle buffer system is the best route.
I'm no fan of aftermarket springs. If the gun won't work with a mil spec spring, I'd get rid of it.
I didn't know the barrel made that much difference.
Probably the most single important part in the rifle.
Not sure what the BCG has to do with the situation... just buy a good one.
Where it comes into play is if someone is using one of the lightened semi-auto AR15 carriers or a M16 carrier.
IMO manufacturers will always error on the side of realibility. IIRC, Noveske sizes their gas ports so the rifle will run with a H2 buffer but they are shipped with a H buffer.
I like the feel of the recoil with a heavier buffer, but I don't like how it slows the bolt carrier. I'd rather the action be lighter and snappier if that makes sense.
Thanks everyone. That's the kind of information I'm looking for. I haven't decided on the barrel maker yet. Just have the lower, and have stripped upper on the way.
I didn't know the barrel made that much difference. I had assumed the gas port was basically the same on all mid lengths.
Sounds like I have a good starting point.
Middy gas systems have NO TDP so companies just go with what they like. This is the problem with this gas system and only a few companies (like BCM) actually do testing to find the optimal GP size.
IMHO, most of the middy barrels out there are over gassed.
C4
Middy gas systems have NO TDP so companies just go with what they like. This is the problem with this gas system and only a few companies (like BCM) actually do testing to find the optimal GP size.
IMHO, most of the middy barrels out there are over gassed.
C4
Thanks Grant, I'll probably go with you for my BCG, lower parts, and barrel.
Middy gas systems have NO TDP so companies just go with what they like. This is the problem with this gas system and only a few companies (like BCM) actually do testing to find the optimal GP size.
IMHO, most of the middy barrels out there are over gassed.
C4
This is why I only buy BCM complete uppers.
My BCM middy with BCM BCG works in tandem with a carbine buffer.
It works as advertised. What can I say?
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