Is there any good reason to choose an 16" M4 profile barrel over a 16" Lt. Wt. in an semi auto AR? Or even a 14" M4 for that matter? The 16" Lt. Wt. has to be pretty close to the same weight as the 14" M4 and you get a little more velocity out of it. And the length difference is negligible since you have to permanently affix something on the end to make it 16" anyway. Is all the popularity of the M4 just because of the cool factor or is there something I'm missing?

No
No
Yes, yes
True
Yes, no
I have an M4 just because it's cool looking

The 16" LW is nearly 18"' long once you put a flash supressor on it. A bayonet doesnt fit properly either.

A 14.5" M4 Brl with Phantom or Vortex is 16.1" loang, giving you a shorter OAL, and a bayonet fits properly.

Ok so you have roughly an inch and a half more of usable barrel length and you can't hang a bayonet on it. But you get better velocity. And it weighs the same. Wasn't the AR carbine designed as a shooting weapon and not a stabbing weapon? What are you really going to do with a bayonet on a 14.5" carbine anyhow? Or any rifle for that matter? I still don't see the advantages.

14.5" will also give you more flash and noise so you might be more tempted to use the bayonet!

I have one of each and the 14" with the brake to an oal of 16" is pretty cool looking but, the 16" with a brake of about 1" (mine is an older one with an inch flash hider) does give better velocity and the accuracy is very good It will do about 1.5" with an Aimpoint at 100 yds and it weighs less than a 16 HBAR. The AR was origionaly designed to be a light weight weapon, is has gotten away from that and most of it is plastic and aluminum. If I waer to choose a SHTF rifle, it would by the Govt Carbine 6520 with the 16" tube.

Bang bang, shoot shoot.
Happiness is a warm gun.

Bill

In my personal opinion....

To answer your question, it is just the coolness factor. The step cut for the M4 is totally unnecessary unless you are mounting an M203. The heavy weight is not necessary for improved accuracy, etc.

I personally saw this phenomonon with all my fellow officers. I got an early LE M4 when they first came out and people started trading in their lightweight Govt. carbines for the M4's. Some of it was the removable carrying handle, but they ALWAYS got the M4 barrel cut instead of the A3 heavy barrel without it. I mean, you can't be the only dork without a step cut, right?

My ideal carbine would have an OAL of 26.1" and the Brl would measure 16.1" including any muzzle attachments, it would also be as light weight as possible.

Quoted: Quoted: but they ALWAYS got the M4 barrel cut instead of the A3 heavy barrel without it. I mean, you can't be the only dork without a step cut, right? The step cut is not what makes the M4 barrel attractive; it's that the barrel is skinny (think: lightweight) under the handguards, but heavier up front, just like the M16A2 barrel.  This gives better accuracy and heat dissipation without having to carry all the weight of a HBAR.  Step cut or not, the M4 is a better profile unless you shoot tons of ammo on full auto. The question I have is this: why has no one ever made a Mil-Spec quality 14.5" lightweight/A1-profile barrel? -Troy

Your weird. The M4 thing is the step cut, It makes it appealing. Who knows why its thin under the barrel, maybe to dissapate more heat since that part is under the HGs. M4 is a cool factor toy,in these civilian parts.
GG

Well if its in post-ban configuration the bayo lug doesnt exist..so thats a moot point..so I sold my bayonet and bought a glock...the velocity out of the longer barrel is worth it to me...coolness factor notwithstanding

I just sent an M4 type barrel to Kurt.  This was Bushy's "Patrolman Carbine"  whis is M4 prfiled but a full 16 inchs.  it had Mini Y comp bringing the length closer to 18, so I'm having that removed and a Fake Flash supressor put ove a turned down end of the barrel.  My origional upper in an AK short which I'm contemplating sending to Kurt to have the AK brake removed and his A3 brake put on, but I'm also thinking about him turning down the barrel under the handguards to make it lighter.  The first thing I noticed when my upper came in the mail and I threw it on my lower (with a telestyled stock) was the weight/balance diference of an HBar v. M4 barrel.  When I had the A2 stock on the carbine it was fine, but with the fake telescoping stock it was definitely front heavy.  Either that or I'll just get another lower, have him throw on the A3 brake and keep it an HBar carbine with the A2 stock.

dc306      I personally saw this phenomonon with all my fellow officers. I got an early LE M4 when they first came out and people started trading in their lightweight Govt. carbines for the M4's  The next time this happens send him my way. I'd be happy to take that unwanted Govt. Carbine upper off his hands.

troy       The step cut is not what makes the M4 barrel attractive; it's that the barrel is skinny (think: lightweight) under the handguards, but heavier up front, just like the M16A2 barrel. This gives better accuracy and heat dissipation without having to carry all the weight of a HBAR. Step cut or not, the M4 is a better profile unless you shoot tons of ammo on full auto.

The question I have is this: why has no one ever made a Mil-Spec quality 14.5" lightweight/A1-profile barrel? But wouldn't lightweight all the way and an extra inch and a half still be better, like you say unless you are shooting full auto and really need the heat dispersion qualities. Its about the same weight and better velocity which is what this round requires to perform? Forgive my for doubting you. I'm new at this and trying to learn from you experts. Thanks

I'm an idiot.  I rambled so much I forgot to post my points.

1)  I went for the full 16 inch length so I wouldn't "cheat" myself the 1.5 inches the sttandard M4's 14.5 barrel would.  (If someone could point me to the direction of Muzzle velocities of a 14.5, 16 and 20 inch barrels, I'd be interested in seeing this)

2) id I get my HBar turned down, I'll skip the step cut because I like the look of the regular Carbine but would like light weight.  At least I'm debating this.

Vinnie ... not in stone but I have read in reputable places that you loose 50 to 75 fps for each inch you cut off...pat

Quoted: If someone could point me to the direction of Muzzle velocities of a 14.5, 16 and 20 inch barrels, I'd be interested in seeing this)

www.bushmaster.com/faqs/techdatafaqs.asp

I chose a 16" M4 barrel assembly because I wanted something light.  I don't care about the cosmetics.  I just think it's goofy to carry a 16" HBAR.  

If, at the time, I thought I could easily get a 16" lwt. barrel assembly, I would have probably picked it over the M4.  Again.. something light.