I searched and got everything but the answer to this question.
On an M4 “Carbine” do you gain much in handling ability in a 14.5 barrel over 16?
Do you lose much in velocity?
Any other pros/cons to either?
God Bless
In a non NFA weapon you really gain nothing since you need a flash hider that makes up the extra lenth. At best you are Gaining (losing?) an inch or so.
Even though you’re only talking about ~1.5" of overall length, I’ve found it makes a very noticeable difference in handling when handling the rifles in vehicles and other enclosed spaces. If it’s just a range toy, then it would likely have very little benefit…unless your range allows bayonet charges. 
(Can’t mount a standard bayo on a 16" barrel.)
The velocity loss is minimal and your effective range with most types of ammo will be shortened, but the difference small enough to be negligible for my needs…and probably for the vast majority of shooters, as well.
I personally prefer a 14.5 over a 16 if both are using a CAR gas system. I can tell a difference in recoil impulse between the two, and prefer the way the 14.5 feels- however, I have about 50,000 more rounds through 14.5" barrels than 16" barrels and I may just be more familiar/comfortable with that feeling. I can also tell a difference in handling. People keep popping up pointing out that there is a 1.6" muzzle device stuck to the 14.5 barrel (if you are trying to avoid NFA hassle), which brings it up past 16"; well I have news, most 16" barrels have 1.5" (+/-) muzzle devices too, which bring them up to about 17.5". While you might not be saving much barrel length, you are saving some, and you are reducing weight at the muzzle end.
Having a permanently attached FH (once again, if running a 14.5 and circumventing NFA) can be a limiting factor as well. You lose the ability to readily change the barrel, FSB, some handguards, and (obviously) the muzzle device. Now, I really don’t care about that due to my reason for having a 14.5 gun at all, but I can appreciate the issues for those that do.
You do gain some muzzle velocity by going with a 16" barrel, but not as much as if you go with a 16" mid-length. A 16" CAR gas system is a little more violent in extraction than a 14.5" CAR, but the mid-length is better than either in that regard.
One other thing to consider is that buying a 16" upper instead of a 14.5" non-pinned/welded puts you safely outside the possibility of some knuckle-head making legal trouble for you. I had this happen to me when I was trying to get someone to pin/weld my 14.5" upper. While I didn’t do anything wrong, it could have become an issue if the dissenting opinion was down 7 more IQ points.
Personally I have no good reason to own a 16" CAR, not when the 16" middie is so good. Were it not for the mid-length gas system, I would have no personal interest in 16" guns at all. As far as applicable performance goes, there isn’t anything a 16" CAR gun can do that a 14.5" CAR gun can’t, and except for a bit more weight, nothing that a 16" middie can’t do better. If it comes down to splitting hairs about muzzle velocity you might as well just step up to a 17"-18" barrel and decisively end the argument.
Thanks for all the replies. Failure2Stop you answered all my questions very well. Thanks for the effort!
Failure2Stop covered all the bases so I’ll just say having owned both I prefer the 14.5" over the 16" and I do notice a difference in handling, with the edge going to the short one. So do other 16" owners that have tried my 14.5".
Yes, it is only 1.5" but it I can tell a difference, just like I can tell a difference between a 20" and 18.5" shotgun, and prefer the 18.5".
And I agree with F2S that the only 16" I would consider in the future would be a middie.
I’ll add that the mid length is kinda neat. The recoils impulse that others have wrote about is worth noting again. When I bought my first middie, it was a used upper and I didn’t know what it was. After playing with it, training with it, and working on it I decided was GTG. I currently have 3 16" middies and a recently completed 14.5 middie. I wouldn’t not buy a carbine system but if I have my choice I’ll buy the middie everytime.
Thanks alot guys
yeah you rule!
Molon comes through again. Thanks for posting those, Molon!
Great info posted by all.
I would just add that the issues cited above regarding servicing/etc the weapon when the muzzle device is permanently attached can be completely mitigated via systems like the LMT MRP upper or the MGI QCB upper which allow the barrel to be removed easily – they just slide right out. So with these uppers you can just focus on the other trade offs mentioned like handling & velocity. My MRP sports a 14.5" barrel and handles like a dream.
And, adding to the above post, there are great drop in rail systems that don’t require removal of the FSB. I went with the DD Omega on my 14.5" N4.
Buying an SBR or doing a Form 1 for an SBR is less than the cost and hassle of a permanently attached flash hider.
GREAT INFO!
Thanks guys really appreciate everyone’s time and effort to help educate. Molon if we ever meet I owe you a beer;)
God Bless
the only 16 i own, and probably will ever own, is my recce… i see absolutely no reason for a 16" barrel for any other reason, and especially not for a “carbine.” too long, no great velocity or accuracy benefits unless you’re getting a heavy ass stainless match middy 16, always seem to be 1/9 and 4140… they’re kind of silly.
as far as SBRing it- i HATE having to “register” to own any firearm, and when you can easily have a true carbine without SBRing, i think that’s the way to go. If you’re gonna SBR, save it for your suppressed 10.5
in my opinion
$200, right? Are you saying it costs $200 to pin and weld a FS?
Edited to add:
+1
Glad to be of help. In my state the unwashed masses are not allowed to own SBRs, so if I want to have a 14.5" barrel, it has to have a permanently attached extended flash hider. Certainly not the ideal situation, but it definitely beats not having a 14.5" AR at all.
No single AR-15 is ideal for every situation, so I view a 14.5" barreled AR-15 as another tool in my box. Mine serve primarily for defense of hearth and home. Loaded with 5.56 TAP I think they fulfill their role quite well.
14.5" Noveske N4
14.5" Colt M4A1
When you ad up the cost of a long flash hider, labor to weld it on, shipping back and forth, and the devalue of your barrel, yes it is more than $200.
There are also several non monetary drawbacks to a perm FH such as your silencer choice is extremely limited. Your muzzle will pit. You cannot remove the FSB and add a FF rail. You are stuck with one FH.
Scotty thanks
Why would you want a FF Rail on a short carbine? Is there any advantage to it?
Why will your muzzle pit?
God Bless