What barrel length for AR15?

[Alex45ACP]

I'm planning to buy a new Bushmaster AR15 type rifle soon and need to choose a barrel length. I'm stuck between 16 and 20 inch. I'm leaning toward the 20" because I'm not planning to be kicking down doors or anything like that, and a longer barrel should give more velocity. But a friend of mine is telling me to get the 16" because it's lighter and the 4" don't make much difference in velocity. Any input?

BTW the rifle will be used for self defense purposes.

 

[SpookyPistolero]

If you don't really think it's something that will be carried much, I like the idea of the full length barrel much more. Plus you get the rifle length gas system. You could compromise, though, and go with an 18" from somewhere like MSTN.

 

[Alex45ACP]

I'm not planning to carry it. But if I needed to for some reason would the 16" be much better?

 

[SpookyPistolero]

I should probably add the disclaimer that I'm not an AR afficionado. But I don't really believe that the 2" difference is going to make all the difference in the world if you had to go indoors when using it (though you might find the full 20" a bit cumbersome). What might make a difference is having a rifle length gas system instead of the abbreviated version on most 16" examples.

But really there a tons and tons of 16" ARs out there, the owners of which will likely chime in soon, which are perfectly reliable. Probably some who will say that to them, the 20" is still a handy length. My opinions are just based on handling and shooting a few of each example, and other rifles of the same lengths.

If it were my money, and it isn't at all, I'd probably go with the 18".

 

[Kurush]

If you're using it for home defense I'd recommend the 16". The extra barrel length is great for long range target shooting and shooting critters/bad guys at longer ranges but it doesn't sound like that's what you're doing. Here's a link to the 5.56 fragmentation charts: http://www.ar15.com/forums/topic.html?b=3&f=16&t=189353

 

[Too Many Choices!?]

Since it is a DEFENSIVE carbine,

I say the shorter the better! My 14 1/2" barrel with permanantly attatched AK muzzle brake(it's a Bushie), has been drop dead reliable. Even after being dropped and I did think I would die, but that was in my still teething days. Now my AR gets treated like my AK, as a tool. The AR-15 gets treated like precision tool however! If it is a DEFENSIVE carbine, then reach out and touch velocity of a 20" barrel really isn't needed. My M4 will easily handle anything inside of 200yds. If you need more stopping power at range than that on your defensive carbine, I would say you should either get a 24" barrel or move up to .308 out of an AR-10 or M1A varient !!! Because arguably anything greater than 200yds away and you should probably have more options. The extra barrel only gives you a little more oomph at range, while giving up mobility/swingability, and with proper bullet selection you will get back SOME of the stopping power at range that the shorter barrel gives up(soft points, heavier bullets and hollow points are options).

 

[Harry Tuttle]

for defensive use, bayonets mount up weird on 16 inch barrels

 

[GoRon]

Get both


I have a 16" and I'm in the process of getting a 20". This is what happens, you feel compelled to buy "things" for your AR, you feel compelled to buy a second one set up for different applications.

 

[Alex45ACP]

Is it possible to switch barrel lengths? Like get a 16" and put a 20" on later?

 

[boing]

Yes. With a few tools (barrel nut wrench, receiver block, pin punch for the gas tube), any dope can swap barrels on an AR. I've done it, even. Headspace is determined by the manufacturing tolerances of the bolt and the barrel extension, so that shouldn't be a problem given parts of reputable manufacture. Still a good idea to have the headspace checked after barrel swap, though.

You'll need new handguards and gas tube to fit the new barrel.

The easier way is to just get a new, complete upper receiver/barrel assembly in the configuration you want: push the two pins, swap the uppers, done. It's more expensive that way, but more versatile, and much less of a hassle.

 

[GoRon]

You can buy complete uppers.

Then all it takes is seconds to switch uppers.

I don't know about using a carbine upper on a lower with a rifle buffer and spring.

Now that the question is out there someone who knows for sure will let us know

 

[boing]

Standard "rifle" buffer/spring will work fine with a carbine upper. During the AWB, tons of ARs in this configuration were sold (Bushmaster Shorty, etc...)

 

[1911 guy]

Personal / Practical

Personally, I like the 20" barrel since I use mine for everything from bedside to paper punching to coyotes. Practically, the 16" setups are popular and manufacturers have got them running as reliable as any other configuration. I'd get the lenght you itch for now, then buy another complete upper later.

 

[Bartholomew Roberts]

The 16" barrels are popular because being shorter and lighter, they make for a very handy rifle. If you go with a 20" barrel, getting a government profile barrel (light underneath the handguards, heavy forward of the front sight base) will help the handling of the rifle.

Since all the parts on the AR were originally designed around the 20" barrel and rifle length gas system, the rifle will have a slight edge in durability and reliability. However, they now make 16" barrels with midlength gas systems that reduce the gas pressures to make it more inline with the rifle and give you a little extra sight radius as well.

As to the collapsible stock/fixed stock, you can use any stock with any length barrel, you just have to make sure to use the carbine buffer with short carbine stocks and the rifle buffer with fixed A1/A2 stocks. If you run a really short barrel (10.5" or less), you'll need a new heavier buffer and may still see the occasional reliability issue.

 

[NMshooter]

Either 16" or 20" work great, especially if you get a light profile barrel.

Matter of fact the 20" is much more user friendly when it is an A2 profile barrel.

You can stick a collapsible stock on any barrel length or gas system length, and I recommend an "H" buffer if you do so.

And get a flat top upper receiver, even if you want to start with a carry handle, because sooner or later you will appreciate the ability to remove it and attach anything you want on there.

Hope this helps.

 

[Kurush]

Just to confuse you a bit more, you could also get a LMT monolithic rail platform (MRP) upper and get different length quick-change barrels. You'd still have to stay above 16" of course unless you get a stamp.

 

[Mulliga]

I vote 20" A1-profile - light, easy-to-handle, reliable, and has that extra 100 fps.

 

[1911user]

I'm planning to buy a new Bushmaster AR15 type rifle soon and need to choose a barrel length. I'm stuck between 16 and 20 inch. I'm leaning toward the 20" because I'm not planning to be kicking down doors or anything like that, and a longer barrel should give more velocity. But a friend of mine is telling me to get the 16" because it's lighter and the 4" don't make much difference in velocity. Any input?

BTW the rifle will be used for self defense purposes.

If you don't require a short barrel, then choose the ammo first and a barrel to work with it.

It's hard to go wrong with either length, just don't get a 20 inch HBAR version. If 20", get the govt. profile barrel and lose a pound of metal while making it balance much better. For the 16 inch barrel, a mid-length gas system is better, but you may have to go with RRA (or a custom barrel) to get one. I don't think bushmaster sells barrels with mid-length gas systems.

If you are using FMJ (M193 and ss109) ammo and are counting on bullet fragmentation then the longer barrel makes a nice difference in effective range.

If you get into ARs, you'll likely end up with both so which do you want to start with????

 

[Alex45ACP]

The 16" barrels are popular because being shorter and lighter, they make for a very handy rifle. If you go with a 20" barrel, getting a government profile barrel (light underneath the handguards, heavy forward of the front sight base) will help the handling of the rifle.

I think I’m going to get this rifle: http://www.bushmaster.com/shopping/weapons/bcwa2s20.asp

Is that set up the way you describe?

And get a flat top upper receiver, even if you want to start with a carry handle, because sooner or later you will appreciate the ability to remove it and attach anything you want on there.

That is the A3 version, right?

It's hard to go wrong with either length, just don't get a 20 inch HBAR version.

What is HBAR?

 

[Sunray]

"...the 4" don't make much difference in velocity..." Your buddy is confused. You lose about 100 fps per inch. All these short barreled AR's are marketing things.

 

[Too Many Choices!?]

H-Bar = Heavy Barreled model of AR

This will mean it has all the great qualities of being cheaper for the manufacturer to make(as it spends less time being profiled), should be stiffer (less susceptible to,'barrel whip"), a hell of a lot heavier up front(which can help dampen muzzle jump), and able stay more accurate as the barrel heats up durng rapid, or prolonged fire sessions(H-bars supposedly tranfer or dissipate heat more evenly too) . Some say it's a gimmick. I say my H-Bar M4A3 with 14 1/2" barrel is very consistent, even when it's too hot to touch the barrel! TIFWIW .When it comes to the AR-15, you literally have Too Many Choices!?

PS- I also think a 20" H-bar is a bit much to attempt holding up from shot to shot .Oh yeah, my PDW AR-pistol is a 10 1/4" H-bar.

 

[Alex45ACP]

http://www.bushmaster.com/shopping/weapons/bcwa2s20.asp

Is that in HBAR? That is the rifle I'm probably going to buy.

 

[1911user]

http://www.bushmaster.com/shopping/weapons/bcwa2s20.asp

Is that in HBAR? That is the rifle I'm probably going to buy.

I'd bet money it is. For hi-power and target shooting, a heavier barrel makes sense. For a rifle (carbine) that is going to be carried much, the govt. profile is more desirable. Here's a link showing the govt. profile. The difference is only under the handgaurds (not installed in this pic): http://www.bushmaster.com/shopping/barrel-assemblies/abbl-20a2.asp
Compare with this pic (HBAR): http://www.bushmaster.com/shopping/barrel-assemblies/pbbl-20a.asp

Heavy barrels are not so bad on shorter barrels since the weight is closer to the center of the rifle. They aren't "light" but seem to balance better than 20" heavy barrels. You really ought to handle several different AR configurations and see what feels good to you.

You might also want to spend some time reading in the AR-15 secion of ar15.com, lots of good info there.

 

[artherd]

I say go 18" or 17" is the shortest you can go and keep a 'rifle' gas system.

I have a 20" right now and like it, but it's not the best close-in high-manuverable gun.

I think mid-lightweight profile 17" AR is about perfect.

 

[salty]

Length does make a difference - 16" for under 200 m and 20" for over to maintian velocities. I would buy the 20" as it will cover more situations than the 16" as you stated it is not a defense weapon. If you get a 16" at least get the Bushmaster diaspator model.