14" vs. 16" AR-15

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Frog48

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I've tried doing a search, but relevant info is hard to pick out between useless posts. Anyway...

I'm looking at Bushmasters are a local shop. One model has a 16" barrel with birdcage flashhider, the other is 14" with extended fixed Izzy flashhider (to make it legal length). Otherwise, the rifles are identical... all the fun stuff: A3 removable carry handle, 6-position collapsable stock, etc. Price difference between the two is negligible, so thats a non-factor.

Is there any noticable difference in accuracy or performance that I should be aware of, before making a decision?
 
I don't know alot about the 14" barrel, but they just seem quite pointless...If they end up being the same length, why in the world would you not want the extra 2 inches of barrel?
 
Thats what I was thinking.

I was just wondering if there is any advantage to a 14" with Izzy. I cant think of any, thats why I'm posting the question to yall. :D
 
14.5" Bushie with permanent AK brake...

The accuracy thing is a non issue... The only difference is in muzzle velocity, which between 14 and 16 inchers is negligible. Mine is for short range use anyway(150 yards and under) so muzzle velocity at those rangs is not a problem. I wanted the shortest non-NFA firearm I could get, so the 14.5" plus perma brake works out. If you add a suppressor or brake to your 16" of barrel, you are now into the almost 18"+ area, something to think about... Just my .02 cents on the matter, YMMV...

Still 2 Many Choices!?
 
I agree...

The accuracy thing is a non issue... The only difference is in muzzle velocity, which between 14 and 16 inchers is negligible.
Click to expand...

But I disagree.

Let me ‘splain:

The accuracy is not going to differ much, but the barrel length of an AR becomes very important once you get shorter than 16”, and not only because of velocity. Shorter than 16”, most loads are not using all the powder to propel the round. I know that in a 16” BBL, you still have that, but it gets worse the shorter that you get, and the problem is not linear, but rather parabolic. This leads to low muzzle velocities which leads to problem #2. The .223/5.56 relies on velocity to fragment properly. Shorten the barrel, loose velocity, and your bullets lose reliable fragmentation range. The third thing is short AR’s are more temperamental with regards to properly cycling. As you shorten the barrel, you have a shorter period of time to achieve proper bolt operation pressure in the gas system, as well as a shorter "dwell time". This means that function will vary more from bullet weight to bullet weight, and from manufacturer to manufacturer.
In “The Book of the AR”, which is actually a magazine; they did an extensive test of this. Pick up a copy and check it out, the results are surprising.
 
I'd take the slightly increased velocity of the 16" barrel over the 14". 16" is short enough as it is for a .223.
 
Thanks guys. I guess I'll wait a week or so for an unopened 16" to get in-stock. The shop has several 14" in stock, but only the display/floor model of the 16", and I want one that is untouched. :D
 
One thing to remember is that 16" is just the barrel length. If you go with a 14.5" or 14.7" barrel with a flash suppressor pinned on for legality, you have 16" of barrel length total including the flash suppressor. On a 16" barrel, you also gain somewhere around an inch or so with the addition of the flash suppressor. Right now, my personal M-4gery has a 16" barrel but I'm thinking of going with a 14.7" to more closely match my M-4 at work.
 
I'm sure if top velocity and accuracy were the goal you would be looking at at least a 20" AR, but looking at the M4 style, Short range (100 yds and under) shooting, light weight and easy handling are better, why not go with the 14.5", also seems to balance better, a couple ounces less at the end. I have found ammo selection and maintenence have more impact on AR reliability than barrell length. With m193 or ss109 ammo if the round goes bang the gun won't jam, but with winchester or UMC saami spec ammo, mine will short cycle maybe once or twice in a 30rd clip.
 
14" ARs are a no-go for me because they require either to be registered as SBR, or you have to permanently attach muzzle devices. :barf: to those proposals.

Perm. attaching a muzzle device isn't a bad thing, so long as your are committed to keeping the rifle as-is. I like to be able to work on an AR without needing to grind, cut, weld or torch it...
 
All good point! Now I'm even more confused than when I started... I guess I'm gonna just go back and handle both again, and see which rubs me the right way.

I know its tough to tell based simply on a photo, but can anyone tell me about this rifle, if it is 14" or 16" (or something else)? This is the look I'm looking for:

BushmasterM-45.gif
 
Really freaking loud versus very loud. Less velocity in a round that depends on it for positive terminal results. What is the point of the 14"?
 
I have one of each!

The 16" is more flexible in terms of later potential upgrades. I would say it's hard to beat the 16" length in general...
 
reread my post

Short range (100 yds and under) shooting, light weight and easy handling are better, why not go with the 14.5",
Click to expand...

even with the 14, the overall length is the same as a 16, so why give up the velocity?
 
Yeah, but the 16" with flashhider becomes a 17"...:p

If you absolutely want the shortest possible set up, with a flashhider and the most barrel you can get behind it, and you don't want to go SBR, and you're not going to take it apart anytime soon - get the 14.5" with perm attached A2.

If 1" doesn't matter to you, get the 16" so you can easily work on the rifle down the road. Velocity is also a gain, not a huge gain, but a gain. Some will argue the extra few yards of fragmentation range is meaningless on a carbine meant to be used out to 50 or 75 yards max. That's for you to decide.


Remember one thing though, the more muzzle velocity, the greater the fragmentation even at short ranges. A bullet striking at 3,000fps is going to shatter more/worse than one at 2,750fps. So velocity does make a small difference, even when you are within the fragmentation range. A lot of people think so long as they are within range, they're good to go. That's true, but a 20" rifle will be more effective than a 14.5" rifle at 50 yards, regardless of the fact that they are both well under their max frag range.
 
The Military chose the 14.5" barrel length for one simple reason.

A 14.5" barrel length allows a bayonet to be mounted to the weapon.
A 16" barrel is too long to accept a bayonet.
 
Wha What What

A 16" barrel is too long to accept a bayonet.
Click to expand...

What are you smoking and where can we get some?

You can mount a bayonet on a 16"bbl... hell, you can mount one on a 20"bbl.

In an AR, you are giving up about 60fps per inch with a bullet 55gr and under, about 35-40 per inch with 55-68, and 20-30 with 68 and up. it may not sound like much, but out of a 16" bbl, the velocity of a .223 is already dangerously low for the purposes of fragmentation.

Let us not also for get the reliability issues. Shorter AR are not as reliable as longer ones, and are much more tempermental.
 
Muzzle V is the gating factor on the AR platform.

IMO, the effectiveness of the 5.56 cartridge is entirely sensitive to bullet design, and whether they expand or fragment, bullet designs are sensitive to muzzle velocity.

Above a certain velocity, the bullets perform as designed, with devestating effect. (IIRC, it's 2700 fps for M193, a fragmenting design) Below a certain velocity, they pretty much make straight .22 caliber holes.

Basically, what this means is that there is a range at which a bullet in flight will drop below whatever the threshold of effectiveness is for that design, and the higher the initial muzzle V, the further out that range is.

Here's an eye opening table from the 5.56 ammo faq:

http://www.ammo-oracle.com/body.htm#fragrange

Distance to 2700 fps:

20" Barrel 16" Barrel 14.5" Barrel 11.5" Barrel
M193 190-200m 140-150m 95-100m 40-45m
M855 140-150m 90-95m 45-50m 12-15m

So,to answer your question, going w/ the 14" barrel basically lops 50 meters off your already short baseline range of 150 meters. W/ M855, you've basically got a 50 meter gun, and might as well use a #4 buckshot. :neener:
 
The Military chose the 14.5" barrel length for one simple reason.
Click to expand...

Actually, it was because that was the shortest Colt found that they could go without sacrificing too much reliability at the time.
 
I'd go with the 16" anyday. However, 20" would be my choice for accuracy due to the longer sight radius.
Click to expand...
You can get that longer sight radius with a 16" barrel in the Bushmaster Dissipator.
 
Sight radius shouldn't be that big of a deal, if you really want to be accurate you'll be using a quality optic.
 
DogBonz said:
Onmilo said:
A 16" barrel is too long to accept a bayonet.
Click to expand...
What are you smoking and where can we get some?
You can mount a bayonet on a 16"bbl... hell, you can mount one on a 20"bbl.
Click to expand...

Actually, Onmilo is partially right. On 16" barrels with M4 or CAR length handguards, the FSB is located too far back for a standard bayonet to attach properly.

14.5" with the shorter handguards, 16" with mid-length handguards, and 20" with regular handguards all should affix a bayonet properly.

I have seen bayonets with longer handles designed to work around this.
 
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