Barrel Length on AR15

I am going to build an AR15. I have no clue what I am doing, but the first thing I have decided to figure out is barrel length and gas system length. I want a gun for a survival situation, but also self defense. What should my build look like?

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I will come back to view comments as often as I can but I will not be constantly watching.

20" pencil barrel 1:12 twist. Triangle handguards. M193. It ain't me.

14.5" pinned and welded midlength gas with an A5 buffer.

y?

I am leaning towards 14.5 barrel because of military lol, I mean wouldn't they have the best gear? Why the mid length gas though? Won't it be too much?

.223/5.56 performs best out of a twenty inch barrel. Shorter is slightly handier though, especially when getting in or out of vehicles. Make of that what you will. I myself went with a sixteen inch for convenience, but now I want a twenty as well. Had I gone with the twenty I'd want a sixteen though. You could get both, if the cost is too much just get one lower and both uppers and switch them around. If you find one you vastly prefer, sell the other.

The reality is you probably won't notice much difference. I've fired both and can't really tell any, which makes sense given the only real difference is muzzle velocity and I'm shooting paper. The twenty is slightly more inconvenient, but only slightly. Like I said, you'll notice it getting in and out of cars with it slung, but if you are anything like me you'll almost never do that. As a survival rifle shorter might be better, especially if you ever wanted to break it down and carry it in a bag or something.

For when the trees start speaking Vietnamese

>I want a gun for a survival situation, but also self defense.
Depends. Home defense, indoors, with an AR, is not ideal. ARs are loud (as in the concussion will literally shake paint off the walls), expensive, and prone to over-penetration. If you want to defend yourself indoors, get a 12 gauge.

Now, if you mean survival and self defense as in an unlikely SHTF scenario, you'll want something light and easy to carry over long distances. Since the average Joe will never engage a target beyond 400 yards, anything longer than 16" will be dead weight. Get a 16" barrel with a mid-length gas system (carbine is slightly over gassed).

No midlength gas makes for a smoother recoil impulse which makes the rifle nicer to shoot. And with a 14.5" barrel you shouldn't have issues with dwell time.

3 gunners use Rifle lenght because of of less recoil though it adds some time as the gas has to travel further. you can use it with a 20 or 16 obviously longer gives bullets more fps

This is the impression I have been getting. I will most likely go with 16 mid length. Thanks!

Don't listen that is the most wrong statement I've heard on Jow Forums this month

16" with midlength gas system is a good combo

Build a Dissipator like this one, also use 55gr for home defense since it actually penetrates less than some buckshot loads.

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Military gear is whatever was deemed acceptable at the lowest price point. Civilian ARs left military M4s behind years ago.
But is right. A 14.5 in middy makes an exceptionally smooth-shooting gun, and the A5 buffer is pretty tight. I like mine a lot.

Ok then that is likely what I will do considering I wanted a shorter barrel anyway. Also I was gonna go with 556 nato

16" is optimal. Enough velocity to shoot long distances, nothing more than necessary.

Ok then that is likely what I will do considering I wanted a shorter barrel anyway. Also I was gonna go with 556 nato

Excellent choice. Check out faxon gunner taper.

Dissipators are fucking aesthetic.

5.56 nato is fine, especially if it's your first build. Remember that if you go 14.5, you need to have a gunsmith pin and weld your muzzle device otherwise you need an SBR stamp.

there is so much wrong in this post. It is made of Fail and Aids.

That sounds like such a hassle, I think I will just have to go with 16 then, I don't want to pay 200 dollars. Or I guess someone says I can just transport it with the upper and lower disconnected lol.

>That sounds like such a hassle
It really, really isn't.

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I'm looking at laws specifically for my area and I can tell you it will be a long difficult process. On top of that I know little to nothing about guns.

>Send in barrel to ADCO
>Pay them $30
>Muzzle is pinned and welded
>Get barrel back three days later
It's literally more difficult to renew your driver's license.

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another point to add to this, it's also subject to whatever objectives they have and politics of all involved stakeholders (for example, the existence of the AR forward assist, or the caliber of the FAL)

don't be surprised if the use cases of the various military branches 50 years ago don't match yours today

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How come red loctite is enough to count a "brace" permanently affixed but not a muzzle device?

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Sorry, does that mean the muzzle is now part of the barrel and the barrel is now over 16 in?

OK watched a vid on it. If ur still here I have most likely decided that for now since this is my first gun I will go for the 16 inches so I can continue to modify the gun if I want to until I figure out what works best for me. So perhaps my second gun could be a 14.5?

I just bought an 8.5" cowards

20" barrel.
Carbines are memes

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Then why not get that same length in barrel? If it has to be longer, just get the barrel, jeez.

20" pencil barrels are not as common as they should be.

18" rifle length gas system. Your choice in twist rate but most common ammo is 55g .223 so I'd go with a 1:9 or a 1:8 if you find a good deal.

12.5" as our lord and savior John Noveske had his. Then throw on a short can and still be under 16". I've made repeatable hits out to 600 yards with my setup.

>Prone to over penetration
What the fuck? Handguns are prone to over penetrate more than 223. It fucking dissolves on contact basically and was never designed to do anything other than penetrate the shittiest of helmets at a good distance. It's by no means a rifle to hurt things on the other side of dense objects like walls or vehicles.

>Anything longer than 16" will be dead weight
Except 150fps more muzzle velocity, greater accuracy at range and legitimately negligible 6oz or less more weight.

Maybe stop adding lasers range finders bayonets flash lights IR illuminstors and shit to your rifle and you wouldn't be concerned with weight from just the barrel.

>permanently attaching an A2 birdcage to your barrel when there's so many better options out there for literally any purpose.

>greater accuracy at range
False, quite the opposite is likely. Short barrels will be stiffer and not flex as much when fired. Group wise they tend to produce better results, it's just you have less muzzle velocity so not as much energy and quicker drop on the round.

Well your opinions don't matter compared to facts, buddy. Ballistics is a well understood concept and it's well understood that accuracy and velocity between barrel sizes for one of the most popular guns ever made.

18" barrels of comparable quality and materials perform better past 100 yards in every way. Velocity and accuracy. This is called fire superiority.

The only suffer from minor disadvantages in weight and mobility indoors where you're better off with a 10.5 or 14.5 inch variant. Which again is gonna have extreme disadvantages outside of clearing a building.

All of my buddies HATE m4's and love their 20" m16's because muh fire superiority and sniper capabilities. Most military engagements happen between 100-500 yards which is a big ass distance. And in SHTF your engagements aren't gonna follow the 21ft standard. You'll be involved with engagements between arms reach and 300 yards depending on where you live even longer as you'll be taking fire from many types of people who have no intentions of confronting you, just taking your shit.

He's right, you're a moron. Short barrels flex less, leading to smaller groups, within the range most people shoot at. Now, shooting a 8" barrel vs a 16" barrel over 400 yards, that's going to be a victory for the 16". At 100 yards though, the 8" will win.

It won't, and this is proven but okay.

You're actually both morons, and so am I. The reason a short barrel will lose accuracy (and accuracy only) to a longer barrel at longer ranges is because its projectile spends more time in the air because it's moving slower. In a perfectly controlled range, where the air is perfectly stagnant, or better yet in vacuum, the 8" barrel will win, all other things being equal. Barrels ring like a tuning fork when a gun is fired, and the tip traces out a little figure 8. The tip is literally flopping around like a floppy penis, and a shorter barrel flops less.

Now, if you're tuning your ammunition for your particular rifle, and you've gotten your powder & primer just right for your rifle so the bullet is leaving the barrel at the exact same point in the flop, and the shorter barreled rifle is just shooting whatever ammo you found at the store, then this is the only time when a longer barrel will be more accurate, but that's not an even contest now is it?

I just spent 7 hours in paint for you
x is greater than y
x creates a larger group size than y

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Your explanation shows an elementary understanding of the amalgamated 60 years of study this weapon has undergone through professional and community testings and experimentation. While it sounds like you make sense and could in some universe make sense, it's not practically applied to the real world and tighter groups are consistently measured with longer barrels which is why snipers have 24-30+ inch barrels on average.

You're deliberately not putting constraints on your use cases to try and salvage some shreds of your waning self-respect. Snipers shoot from long range because it's safer. Longer ranges need longer barrels, and their accuracy benefits as a side effect due to the bullet spending less time being blown around by wind. If your theoretical and I suspect vicarious sniper is in space, or is using a magical new powder that can get 24-30+ inch velocities out of 12" of barrel, then he would use the shorter barrel and get better accuracy.

You're making arguments based on nonexistent circumstances that don't involve real life. We don't use AR's in space.

The longer the barrel, the better the accuracy, and the faster the bullet. This is solved science and ballistics and no amount of space arguments are going to change that you basement theorist. Go outside and shoot your fucking rifle.

>the longer the barrel, the better the accuracy, and the faster the bullet
No, it's the longer the barrel, the faster the bullet, the less time the bullet is affected by gravity and air, THEREFORE the better the accuracy. At short ranges a shorter barrel makes smaller groups.

Also your 7.5-10 inch Barrels have fist sized MOA's or bigger at 100 yards. You keep mentioning silly space vacuum mechanics with no wind or air resistance but didn't stop once to think about gyroscopic properties, stabilization, bullet weight or projectile shape.

Trust me, bud. If I shoot a 10 inch rifle at 100 yards, the 18 inch rifle shooting at a target 101 yards which makes up the difference in air travel from barrel lengths.

This is wrong.

I only like 20" inch barrels, they're aesthetic

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he says around a mouthful of cock

a 16 inch middy is nearly as reliable as the original 20 inch rifle length. you're not going to get the most out of 223/556 with it, but you'll be able to maneuver a lot better with it. i'd not recommend getting into nfa lengths if this is your first build, but i'd also recommend not building one if you don't already own an ar. or you could do what everyone on the internet does and do a poverty pony lower with a psa kit. if you fuck up the lower, you can just get another one cheap as shit.

in my experience, an 18 inch rifle length gas is the best all around. however if you're doing a "survival" build, i'd stick to a setup that would contain standardized/readily available parts in case something broke. middies and carbines run rampant in the market right now.

Jesus fuck

This is a new breed of bait.

A2 birdcages look classic and hide flash fine, all while being absurdly cheap. And a 14.5 midlength already has no recoil so a brake is redundant. There's a reason it's the gold standard for AR15 muzzle devices.

Anyone know any manufacturers that make 1:9 twist pencil barrels in 20" rifle and/or 16" mid?

I wanted to hide my muzzle flash and it has long since proven its effectiveness in that regard and if I want it removed it's a $20 job away and I'll be out of a $3 part. I was going to put a SF3P on my 11.5 SBR but now it's getting a good ol' A2, just for you. Dum betch.

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Why wouldnt you build your first AR? Its not a fucking ak, a slightly mechanically inclined retard could put one together just fine with a few tools.

Does a gunsmith have to weld the muzzle device? Im a pro welder and would love to have a nice pretty bead on my tiny ar

Nope. You can do it.

Isn't that guy agreeing with you? He just said a higher velocity will help counteract the various random factors of firing inside an atmosphere hence it would be more accurate.

Also your final statement makes no sense.

It has to be pinned -and- welded to be compliant. It's still a simple procedure, you drill a hole through the base of whatever muzzle device you're using and then dimple to the muzzle of the barrel. A pin is inserted into the hole, when then presses into the dimple. The pin is then welded in place. If you have a drill press you're set, but places like ADCO do it for a song and dance and they make it look pretty good.

Maybe I should build an AR pistol?

I build one but ended up selling it. Very "meh" experience.

Might as well go SBR in this era of one week approvals.

One week approvals you say? I live in Illinois I looked up the process seemed like more than just an application. Something about another kind of license. People also said it might even take a year, and considering just my FOID took 6 months more than it should have...

Just got my last eform back in 14 days. I think 10-15 days is the average waiting time right now.

Sure it does. He's saying that the difference in barrel length, 8 inches or so, is enough air travel distance to cause a significant difference in group size.

If this were the case, placing your target further back would compensate the distance and his """thesis""" would be proven. But placing a target a foot further back on a longer barrel isn't going to provide the group size he is claiming because of another foot of air travel time

>Can't go across state lines without asking ATF
>Can't sell without asking ATF
>Actually using it in self defense makes it a federal case
Braces work fine, just build a pistol.

>filling out a form once a year is hard
>I sell my guns because I'm poor
>I use SBRs for my carry/HD gun
faggot

>I like to spend money and inconvenience myself for bragging rights on a Yemenese rain-dancing forum

nigger

>the cries of a terminally butthurt poorfag

If you say so ATF ass-kisser. I bet you're glad bumpatocks got banned, too, eh?

ADCO is GOAT

>Can't go across state lines without asking ATF
False, all you do notify them via filling out a short and simple form. You're not asking dick, you're telling them what you're doing and they don't have any say in it.
>Can't sell without asking ATF
Also false, you have a number of options available to you should you ever want to sell an SBR, ranging from having an FFL cosign it and handling everything to simply having the buyer apply for the tax stamp.
>Actually using it in self defense makes it a federal case
100% false, it will only turn into that if it was unregistered or illegal in any way.

You were 0 for 3, I'm amazed you didn't say you had to have a safe to keep the SBR in like I heard another mouthbreather claim.

Really wonder what the deal is with these people making it seem like having an SBR is a huge pain when the worst part (the wait) was reduced to practically nothing recently.

What doesn't get talked about much is that barrel profile is a big factor on how easily it handles.
A pencil profile barrel is WAY easier to swing around than an M4 profile.

The usual suspects. Ignorance and sour grapes. For some reason, brace fags are the worst offenders.

Muzzle devices are a meme. Unless you have an extremely specific need like needing to keep targets in your FOV at 500 yards or trying to squeeze out every last bit of performance from a racegun, you're gonna be fine with an A2. Stop falling for the ""upgrade"" memes and putting useless crap on your guns. The only accessories that actually make a difference on a quality AR are optics, triggers, lights, and ergonomic features like slings and stocks to fit your body.

There are brakes out there that will do a good deal to mitigate recoil. However these are ARs we're talking here so recoil was never that much of a factor to begin with, and this especially applies if it's something like a 14.5" midlength like being discussed here that already has an inherently gentle recoil impulse. With flash hiders it's another thing though, the sheer cheapness and effectiveness of the A2 makes the law of diminishing returns come in like an out of control freight train. It does its job fantastically, so while there are certainly flash hiders that do it better they sure as shit aren't going to reduce flash 10x as much as an A2 despite costing 10x as much.

This is what I have, and im highspeed low drag .

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Yeah a shotgun going off indoors will be noticeably quieter than an AR 15 I'm sure.

Not OP but for a weak bitch like me which would be better recoil wise? And do you guys have an image or site or whatever to walk you through the AR15 parts to get? I've got the lower and that's it. Though says midlength is smoother so I'll go that less I am mistaken. Not 14.5 as I am not looking to SBR it though. Or do the welding

>live right next to state lines

Oh god that sounds awful.

OP I RECOMMEND GETTING A 12 GAUGE FOR HOME DEFENSE BECAUSE THE STOPPING POWER IS UNPARALLELED

WHAT, BECOME A MAGE? DON'T LISTEN TO THIS GUY. MAGIC ISN'T REAL. AND HE'S FUCKING CRAZY. WHAT DID HE SAY, SINCE TAVERN MOE IS ENGAGED TO MARGARET ANYTHING LONGER THAN SEX TIME IS GAY? FUCKING HELL MAN.

it does, fortunately the user is retarded and is saying bullshit

I just came here to post this pic related

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WHAT DID YOU SAY ABOUT MY MOTHER

He's saying the increase in velocity that a longer barrel typically gives makes the difference, not the physical barrier to wind & shit over those few inches, retard

>You're deliberately not putting constraints on your use cases to try and salvage some shreds of your waning self-respect. Snipers shoot from long range because it's safer. Longer ranges need longer barrels, and their accuracy benefits as a side effect due to the bullet spending less time being blown around by wind. If your theoretical and I suspect vicarious sniper is in space, or is using a magical new powder that can get 24-30+ inch velocities out of 12" of barrel, then he would use the shorter barrel and get better accuracy.
>And their accuracy benefits as a result of now being blown around by wind

Read what he is saying retard. If what he was saying accurate, then my grip at 101 yards with an 18" barrel should be consistent with my group at 100 yards with a 10" barrel. Because the bullet is spending more time being blown around by wind.

His case is almost entirely based around some random theory he pulled out of his ass firing a gun in deep space vacuum and observing, neigh, entirely creating a new theory on space ballistics and research on how bullets and barrels react in a vacuum where no kind of resistances whatsoever effect the bullet.

20 in
1:7 twist
Heavy Barrel Contour

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Cover your bases with your first rifle. You'll always regret not having the 20 inch barrel,as well as the compact short barrel. Start out with a 16 inch barrel with a folding stock. Then branch out from there into close quarters, and long range rifles. Still wish I got a 20 inch barrel for the USMC + extra reach factor, but I know I'm good with the 16''. You will be to. Right now I have a 12 inch upper sitting around for my next build. I chose it for the fact I can carry it loaded in my car :D

Longer barrels are not more accurate. Long range shooters use longer barrels for velocity in order to effectively hit their target in question.

The USMC actually made a video to prove that barrel length doesn't affect accuracy.

Sup guys, not an AR-15 question but still. Does anyone know the weight of Barrett M82/Serbu BFG-50A barrel? The tube itself, I mean. The outer diameter will also help.

>longer barrels dont improve accuracy
>but then again actually they do

why did you even post

I already have one, reply to OP lol

My DD Mk18 upper is pretty gucci but I still love the M16 esque rifle, even if its all proprietary except for optics and KAC rail.

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When doing a pin & weld on a 14.5" barrel, an A2 birdcage comes out too short to meet the 16" length requirement. You can either buy a spacer (ugly) or an extended A2 birdcage (also ruins the appearance) or you can choose a newer, cooler looking muzzle device that meets the length requirement (Surefire, AAC, BE Meyers etc.) while also offering compatibility with a suppressor should you get one in the future, or has a brake / linear comp / whatever built in to change the feel of the recoil.

This is mainly why people often drop some cash on a fancy muzzle device to get pinned on. Length. The added bonus of some extra features comes in second.