Does choice in gas system really matter?

Why would rifle length not be good for 16"?

>rifle length
>16"
Is that actually what you mean to ask? The answer is because it's very unreliable. It was a thing. They called it a Dissipator. They've pretty much disappeared because mid length is a similar concept but actually works. The first ones were cut down 20" barrels, but some companies produced them from the factory and a handful still do. Most you find nowadays (like the PSA) are just an aesthetic dissipator, the front sight post does not have a gas tube, they use a low-profile gas block further back.

rifle length gas is about 15 inches long
youve got an inch of dwell time
it can be done but its not optimal
most modern dissapators are actually mock with carbine or mid gas and a fake cosmetic fsb

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To make a true rifle-length gas system reliable on a 16" barrel, you have to make the gas port wide enough that any advantage you get from the longer gas system is outweighed by the sheer amount of gas you're letting into the system.

If OP has his heart set on an M4gery, he might consider going mid-length gas on a 14.7" barrel with the permanently affixed flash hider. I have no idea if anyone makes one, but it seems like someone should.

>M4gery
>mid-length gas on a 14.7" barrel
pick one
if its a middy its not a m4gery

This is true right here, OP >>>Personally, my 16" midlength is smoother then my 14.5 midlength. Due to the 14.5 having a slightly larger gas port. Thats done to increase cycling. 14.5 was designed for carbine length gas. I dont have the charts. But the dwell time for 14.5 is best with carbine. It decreases wear. The most reliable is 20" and 18" rifle length gas system. (And very likely higher velocities).
Midlengths were designed for 16"
Only to comply with NFA requirements.

Not if you're a purist. Which OP may well be.

Nevertheless, there seems to be enough of a demand that PSA made one:

ar15news.com/2011/09/21/new-palmetto-state-armory-14-7-hammer-forged-chrome-lined-mid-length-upper/

I forgot to add OP. If you go for a 14.5 pinned and welded. Get a compensator.
May as well take advantage of current tech .The A2 is a great flash hider. But not so good for rapid fire. Because its not a comp.

Carbine on a 16" works great as long as the gas port is .0625 and you are using a high quality recoil spring and an H or H2 buffer.
Colt figured this shit out decades ago.

>Does choice in gas system really matter?

yes. You should ALWAYS get the longest gas system length that is commonly available for your desired barrel length. It makes the recoil impulse smoother and reduces how dirty the rifle gets.

Unless you're cloning, there's no reason to get a shorter gas system length. My 14.5" midlength Faxon runs fantastic.

>14.5 was designed for carbine length gas
That's not true. Carbine gas length was designed and found to be unreliable with 10" barrels in vietnam, thus the xm177e2 had an 11.5" barrel. When the m4 was being developed the military decided they wanted to but a m203 on it, necessitating the 14.5" barrel we see today.

Really, it was a mix of wanting M203, bayonents, and also not wanting excessive muzzle blast and flash with standard flash hider.

Its absolutley true. Your just quoting crap you read online. I have seen the pressure ratings as it relates to dwell time. Carbien gas length is optimal with a 14.5 inch barrel.
Bayonets to be specific

You trigger me so bad I want to strangle you. It doesnt cycle at 10inches BECAUSE THE POWDER IN THE CARTRIGE HASNT BURNED ALL UP. Therefore it cant push the bolt carrier back into battery.

nob

Lots of shit in this thread OP, just remember that A E S T H E T I C S matter more.
Make one with a mid-length gas and a rail for 16" and/or make another upper that is pic-related.

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I always get the feeling the US went with their 14.5" barrels just so they could keep the carbine length gas system and have a useable bayonet lug rather than design a whole new gas system and length. I got nothing to back this hunch up though.
Ideally something you could do is have a midlength gas system and a carbine length FSB with a hole drilled through it to let the gas tube through, then get one of those FSB cutout handguards to both cover the rest of the gas tube and gas block and still look like something some spec ops spooker would use.

In such demand they still make them! /s

>Does choice in gas system really matter?
There is only one choice

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what is a dissapator actually I google it but nobody actually describes how it works

this
essentially its a 20inch with the barrel cut to 16
the oldones used rifle gas
the new ones the visible fsb is cosmetic

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On the subject of gas systems, is there any issue with using a carbine buffer and spring with a rifle length gas system?

I have an 18” barrel with rifle length gas and carbine buffer, it’s worked just fine.

>Does choice in gas system really matter?
Yes.
>Is this actually a big deal?
Not really. Carbine in 16" is not optimal, but it's also not a big deal. For what it's worth, Colt Canada/Diemaco uses carbine length gas in 15.7" barrels.

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The Canadians use a rifle length gas system with a carbine lower and it works great.
Just run it with an H buffer and you should be good to go.

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You could say they've dissipated :^)

BCM doesn't make anything, they source cheap parts and put their logo on it.

It's fine. Get an A5 buffer kit though, it's even better.

they source parts from other companies to their own specifications/tolerances like pretty much every company does and theyve been proven to do a good job at it

Die beste Qualität.

>BCM
>manufacturer

There goes all your credibility. They are Instagram influencers with a laser engraver.

H2 is ideal

Source: Your ass

No, compensators suck to you and everyone around you, ESPECIALLY indoors. Get a flashider and get good. If I remember correctly SOF doesn’t let team memebers as of know during training because of the concussion to team memebers. Get a flash can ideally, you at least might not go deaf when you shoot it indoors.

Hahah what part do you not believe?
They got a couple Instagram guys to be “BCM gunfighters” and shill there stuff.

It’s common knowledge that they don’t make anything, even they admit it. When they sold crappy BCG’s they blamed there OE.

So again, what part do you not believe?

I put a compensator on my first AR build and even shooting outdoors with good earmuffs on it's a loud bitch and produces an uncomfortable concussion. The concussion is even worse for those standing around the shooter. 2/10, would not use one again unless I was going to tactical shooting competitions.

even that seems overkill for rifle length. I use a H3 in my Mk18.

It's what the Canadians found to be the most reliable buffer weight.

>It’s common knowledge that they don’t make anything, even they admit it.

You should have no problem providing a source then

How about Windham or Aero?
Next teir above them would be?
DD? LMT, LWRC, FN, KAC?
I do like my 2009 Colt 6700 20"HBAR. Put a Geissele G2C trigger in it and a quad rail, Tubb flat wire buffer spring and carrier weight. Has a Leupold 1.25-4.5 VXR Patrol on it to comply with CMP Service Rifle optics rules.
A 1-8 woikd be better for all around.
Still has the 1-9 factory barrel.
Thinking maybe a 20" Criterion in 1-8 to shoot the 77 and 80 grains

most reliable would probably mean going down one level in weight to that is optimal with a clean rifle.

>to that
to what*

Idk man, I just read their study and that's the conclusion they came to, so I used it in my rifle/carbine build

>I always get the feeling the US went with their 14.5" barrels just so they could keep the carbine length gas system and have a useable bayonet lug rather than design a whole new gas system and length. I got nothing to back this hunch up though.

I'm pretty certain this is exactly what the specs were based on for the old XM carbines. They kept that dimension for the bayonet and played around with gas port sizes and buffer weight to make it work. Similar to how the M203 step-down was included on the M4 profile barrel, and the A2 was lightweight diameter under the handguard- this was merely to support legacy mounts from the M16A1 and other pencil barrels. Everything else was made heavy because some R&D knobs misinterpreted their obstructed barrel probe readings as barrels bent past the fsb from hard use, when it was actually just fouling built up at the gas port. I have read this somewhere before but I forget the source.

If it's like the M4A1, then the H2 is for dealing with bolt bounce in full auto.
Either H or H2 would probably be 100% in semi.

Probably, I never tried an H1 but the H2 has been 100% so far.

>14.5” barrel
>loctite a bird cage
>tell anyone who asks (no one will) it’s pinned and welded.

h1 or h2 work with probably 90% of configurations anyway.

>Is this actually a big deal?

No. Either a carbine length or midlength rifle will serve you well provided that it’s PROPERLY built by a professional who knows what they’re doing.

If you care to listen, this podcast goes into what makes a good AR a good one.
spreaker.com/episode/16764547

Don’t waste your time ruminating over the smallest bits of which gas system is best. Make sure you have a reliable well built rifle that works well, have it properly zeroed and know your holdovers, spend money on ammo and maybe a local class.

I bought a cheap CBC upper that is 16" carbine length and with a heavy BCG it doesn't slam back that bad like Jow Forums chumps make it seem. You're not going to be doing full auto mag dumps, you won't even notice any difference and it really doesn't matter