For the barrel length ?

Any specific reason(s).

CQB

Use in and out of vehicles, aircraft, Airborne Ops, Tanks.....

OAL with a suppressor is a consideration.

So it would mount the standard bayonet.

I don't know where the dimension came from, but if you're going to have a barrel shorter than 16", then the 14.5" makes the most sense & is the best compromise to me.

I'm just not a fan of shorter barreled guns in 5.56.

MM

One of the main reasons was urban combat as well as all the reasons all the reasons ready_on_the_right stated. I don't know how much was thought about the addition of a suppressor as when the M4 was adopted for widespread issuance (late 90's--my unit in the 10th MTN started receiving them in mid 98 and we were a front line infantry unit) most of the guys who were using suppressors (SF/Delta) at that time weren't using the M-4 but H&K's and were procuring their own weapons. I could be wrong on that last statement however

This ^^^

I know it made jumping with a weapon a lot easier. When Jumping the M-16 sometimes the jumpers would forget to loosen the upper tie down on the weapons case, when they hit the ground the barrel would hit the ground then jam the butt of the rifle into their shoulder/arm pit. It was easy to tell who was a victim of forgetting to untie the upper tie down, they would arrive at the assembly point carrying an arm and shoulder lower than the other, LOL

That's my answer also.

I've thought, for no more than I know, that the length might be the sweet spot. Guess it just bothers me that I can't have one without the ATF BS.

Besides the ATF restrictions, would the 14.5" be a popular choice for many?

I believe it is the shortest it could be and still fit in a standard M16 rifle rack. The bayonet thing could be solved for any barrel length by adjusting the hand guard length and FSB position, so that isn’t the reason.

The 14.5" barrel was chosen as the "sweet spot". It was a combination of reliability and lethality. Any shorter and they ran into long term reliability issues with the gas systems at the time. They also wanted a certain velocity in terms of terminal performance with the ammunition that was issued at that time. I don't remember the numbers specs, etc, but Crane did the testing and I am sure it can all be found online with some digging.

I've got a couple of 14.5". Both have pinned/welded compensators to make them legally 16". I like the length.

I also have four 16" barreled uppers. The difference is not much, but I do appreciate the slightly shorter 14.5".

While not as exact as cutting the same barrel down but we chronographed Colt barrels with M193 and the 14.5” barrel was 80something fps slower than the 16” barrel. And the 16” was almost 100 fps slower than the 20”.

I’ll take the 16” barrel, if I need shorter, I’ll go 11.5”.

Way off topic but majority of units in the Army have turned in their bayonets to drmo. Bayonets have gone the way of the passenger pigeon.

Come on J... Just think of all the slicing and dicing you could do with a good bayonet...

Yeah everyone loves a good ol fashion bayonet charge lol..

Ha ha..

I’d like to see them on police lines at the “mostly peaceful protests”.

Funny (to me anyway) when the "assault weapons bill" was passed under Clinton, one of the things listed was a bayonet lug. I could not help but think, "when was the last time you heard of a drive by bayonetting"?

Thinking they would have come in handy a while back in Portland, firmly mounted out the rear windows.

I've got a 14.5 but it has a permanently attached AK brake, the long one, plus it's an H-bar, so I don't really get the advantage of reduced length or weight.

Just thread protectors on a couple of 16's & do enjoy the decreased OAL.

Also have gone to a thread protector only on my 20" V Match w/scope & can't recall loosing sight pictures since I removed the cage. If I do go back to a muzzle device on this one, it will be a full blown brake to assure getting to see all impacts.

So many variations, I seem to ponder on them a lot.