I have noticed or it seems most people or upgrading to the 16in M4 upper since the AWB expiration and I am considering doing the same. There is not alot of talk about the 11.5 in. w/ 5.5 in. suppressor CAR upper. I know that the shorter rifling can affect ballistics but are there any other down sides to that model(CAR) upper? Any advice is greatly appreciated.

The 11.5/5.5 barrel puts out a huge fireball and is REALLY loud. Accuracy will be reduced to some degree. I have one and like it, but I only bought it because I already had 16" and 20" AR's.

The 11.5"/5.5" set-up is "Old School". Your bullet velocities will suffer like you said. I admit, the looks are more aggressive than a 16" barrel with a Flash Hider, but other than that, there is no real advatage for the 11.5"/5.5" setup.

Even some of the old 5.5" surpressors were pinned. The barrels weren't threaded. After a while they would shake loose.

I just got a Bushmaster PCWA2X 14M4MY. This gun comes with a 14.5" barrel with a welded FH. On hindsight, I would get a 16" barrel instead.

If looks mean alot to you, and you will be using your CAR15 mainly for plinking, the 11.5"/5.5" setup will be OK. But as an all around more versitile weapon would be a 16" Carbine setup on our gun.  The over-all dimensions of the gun will be the same with better range and accuracy.

I noticed that DPMS still sells a 11.5"/5/5" Carbine, and it looks cool.  Practical? Not really. Cool lookin? You betcha.

I'd go with a 14.5" M4 barrel w/ a perm. attached FH.  The 16" M4 barrels are slightly heavier, slightly longer and just don't look right.  

I have one of each back home, an '89 Olympic Arms with the 11.5 & long supressor and a Colt Sporter witha 16" M4 barrel.  Both function reliably.  The Oly is a bit retro but is a bit shorter than the Colt, the Colt a bit lighter.  Both a neat rifles.

My vote 16" M4 over the 11.5 w/5.5" FH. Your still at 16" overall with both, might as well get the most out of it as you can with the additional rifling. If you desire the LOOK of the 11.5, they make FH that will do just that.

I hear what you're saying Rotty.  But the weight difference isn't that much, but the performance of the 16" has a rather large advantage over the 14.5".  Everyone has their own tastes. Sometimes my tastes are more to the practical than most. LOL!

Like besttiller i knew I liked the compact look of a Carbine as opposed to a full sized rifle. Being practical had absolutely nothing to do with my choice here and I admit it. But now that I look back on my choice, I think a 16" barrel would have served me better.

The 11.5"/5.5" configuration of the AR15 has a classic "warrior" look to it.  I do like the look, and someday I may build an AR Similar to the CAR15 configuration.  Too bad there are so many firearms restrictions where I live. Can you imagine....

An A3 setup with a 7.5" barrel (1:9 twist) with an Old School 5.5" flash surpessor on it? A ACOG sight, Beta-C magazine, Ace M4 SOCOM stock, AR15 AMBIDEXTROUS PISTOL GRIP, with an Aluminum Free Floating foregrip to finish it off? Wow....now that would be MY dream AR15...But alas, it can never become a reality for me.

We just went through this last week but the thread was locked and has fallen off my topics.  However, here's my take: the 11.5/5.5 if a "fun" gun and not very practical.  Go with the 16" because you'll get better performance, you won't have to permanently attach a flash suppressor and you'll have plenty of accuracy to reach out and touch those longer ranges.  I have an 11.5/5.5 but only because I have every other configuration already.  To me, the 11.5/5.5 is just for fun and kind cool because it was the original carbine and carried by the LRRP/LRP units in Vietnam...not a big historical monument but I find it cool since I'm a Vietnam buff.

Go with the 16"

My OLY 11.5 barrel with 5.5 flash hider grouped about 6 to 8 inches at 50 yards.  Not worth it to me.  I change out to a 16 inch full profile barrel (before the M4 was around) and it shoots really good.  Sub 1 inch groups at 100 yards with good ammo.  1 to 2 inches at 100 yards with mil-surplus ammo.

By the way if that 5.5 flash hider "falls off" you now have a SBR (short barrel rifle) which is subject to NFA rules.  Mine was attached to never "fall off".

I was in the same dilema, but mostly because a 16 inch M4 pissed me off when a real one is 14.5 but that's a SBR.

So here's what I'm doing, maybe you'll like it.

I'm getting a standard 16 inch CAR, and attaching a slip over flash suppressor to get that "XM look" 'cause I don't much like pencil barrels and then I still get decent velocity.

Then, sometime in the future, I'm gonna SBR it and buy a real M4 and cut the CAR down to a Commando.

Quoted: I hear what you're saying Rotty.  But the weight difference isn't that much, but the performance of the 16" has a rather large advantage over the 14.5".  Everyone has their own tastes. Sometimes my tastes are more to the practical than most. LOL! Like besttiller i knew I liked the compact look of a Carbine as opposed to a full sized rifle. Being practical had absolutely nothing to do with my choice here and I admit it. But now that I look back on my choice, I think a 16" barrel would have served me better. The 11.5"/5.5" configuration of the AR15 has a classic "warrior" look to it.  I do like the look, and someday I may build an AR Similar to the CAR15 configuration.  Too bad there are so many firearms restrictions where I live. Can you imagine.... An A3 setup with a 7.5" barrel (1:9 twist) with an Old School 5.5" flash surpessor on it? A ACOG sight, Beta-C magazine, Ace M4 SOCOM stock, AR15 AMBIDEXTROUS PISTOL GRIP, with an Aluminum Free Floating foregrip to finish it off? Wow....now that would be MY dream AR15...But alas, it can never become a reality for me.

I have both a 16" and a 14.5" barrel and @100 yds. there is no difference between the two, atleast as far as acuracy goes.  I don't know about expansion, etc.  I've only tested against paper.  I personally like the 14.5" better.  It feels and handles better to me.

If you are at all interested in terminal balistics beyond 25 feet or so, do not go with an 11.5" barrel.

Quoted: I was in the same dilema, but mostly because a 16 inch M4 pissed me off when a real one is 14.5 but that's a SBR. So here's what I'm doing, maybe you'll like it. I'm getting a standard 16 inch CAR, and attaching a slip over flash suppressor to get that "XM look" 'cause I don't much like pencil barrels and then I still get decent velocity. Then, sometime in the future, I'm gonna SBR it and buy a real M4 and cut the CAR down to a Commando.

14.5" M4 barrel with a permanently attatched Vortex is the best legal way to go (it is not a SBR with the Vortex).

Quoted: Quoted: I was in the same dilema, but mostly because a 16 inch M4 pissed me off when a real one is 14.5 but that's a SBR. So here's what I'm doing, maybe you'll like it. I'm getting a standard 16 inch CAR, and attaching a slip over flash suppressor to get that "XM look" 'cause I don't much like pencil barrels and then I still get decent velocity. Then, sometime in the future, I'm gonna SBR it and buy a real M4 and cut the CAR down to a Commando. 14.5" M4 barrel with a permanently attatched Vortex is the best legal way to go (it is not a SBR with the Vortex).

I thought about that, but I really want the option of changing out my attachment.

I'm patient. I'll  wait until I can blow cash on the tax and a damn good M4 upper and all that.

Quoted: If you are at all interested in terminal balistics beyond 25 feet or so, do not go with an 11.5" barrel.

Yawn..... Comon, qualify the statement.... WITH STANDARD FMJ AMMMO. Use other stuff and the ballistics are better.


Blanket statements are annoying.



AZ(Proudownerof11.5inches)K9