Pros/cons of each?   Expected usage: general.

[url]ammo-oracle.com[/url]

No practical difference at all other than the 16" bbl is obviously 1-1/2" longer and that much less handy.

-- Chuck

Velocity is a practical difference to me, and if it's a post-ban they'll both be 16" anyway.

Hi Brou,
being pre-ban does not automaically qualify you to run a short barrel.
Less than 16" requires your weapon to be registered as an SBR, whether it is pre or post ban.

that's whay 14.5" barrels all require some sort of muzzle device.

the real question is how to get a 16" barrel length with as much actual barrel as possible to maximize velocity (an extra ~100 FPS is always a nice thing to have ).

there are several good solutions.
check out legal transfers and CMMG

good luck.

alan

I know the rules.  My statement referred to the fact that most preban 16 barrels will have a flash suppressor on them, making them even longer.

14.5 + 2.0 - 0.5 (overlapping) = ~16.0

16.0 + 1.5 - 0.5 (overlapping) = ~17.0


IMHO 16" barrels look kinda long way out there. However there is a significant velocity gain.

I was faced with the very same quandary myself recently and I went with a 16" 1/9. If it helps, here's why I made that choice:

- A 16" has a higher muzzle velocity than a 14.5" Is it a big difference? No,

- I don't like the idea of anything being permanently attached to the muzzle. The chances are low that your brake or FH will get damaged but it can happen and, if it does, you're out of action until a smith can replace the muzzle attachment. Unless you can or want to SBR the rifle, a 14.5" barrel will have to have the brake (post-ban) or flash hider (pre-ban) permanently attached.

- I choose the 1/9 twist because I wanted to be able to use rounds light than 55 gr "just in case". I primarily shoot 55gr and a bit of 62gr so 1/9 works fine with those rounds. A 1/9 twist will stabilize rounds from 45gr to 69gr and some rifles will work fine with 75gr. A 1/7 twist won't work that well with anything lighter than 55gr but it will handle the heavier rounds (75gr +) very well. Check out the Ammunition forum for more info on this subject.

- I already planned on having an AR with a 20" 1/7 bbl for heavier rounds and longer range (150 yds+) stuff anyway. My 16" 1/9 upper is for short to medium range (150 yds or less) AR. I also have collapsible stocks on both of my AR so the extra length of a 16" bbl is not a big deal.

All that being said, I could have just as easily gone with a 16" 1/7" bbl and when I need to replace the 16" bbl, I will revisit the issue. You really can't go wrong with either one. I feel that my reply has covered the most important pros and cons.

The velocity gain from 14.5" to 16" is VERY insignificant.  The amount of bullet drop is almost not noticable over even a few hundred yards.  There is no practical advantage to 16" over 14.5" barrels for an AR15.

PS:  I have never heard of anyone breaking their flash hider except for that bad run of Vortex's which peeled back.  Has anyone here ever damaged their flash hider that was pinned on?

Up to 50m of extra fragmentation threshold for M193 is pretty significant for me.

OK great I baited someone in to play...

Please show me one report of a .223/5.56 shooting a human at 100-150 meters where the lack of fragmentation casued the human to not be incapacitated when M193 was used inside the United States...  OR where MK 262 failed in a shooting of 150-200m.

This must be inside the US borders where our rifles must stay.  

This is why I say the difference is insignificant.  The odds of someone needing a shorter barrel are far greater than somone needing increased incapacitation in a 50 yard envelope past 100 yards for use inside these borders.

If we are talking animals we would use soft points and ballistic tips so I assum the 50 yard enevelope is human targets.

Oh yes:

1/9 16" M193 = 150 yard frag range (this used to be considered all we needed)
1/7 14.5" MK262 = 150 yard frag range (but somehow this is inadequate now?)

OK.  Since you want to play, why don't YOU show me one instance inside the US where M193 was used at 150m or where mk262 was used at 200m.

Can't find any?

You're not always going to have the most optimal ammo in every situation.  I would much rather have the extra 1.5" if that helps fragmentation with whatever I have (I doubt it's gonna be mk262 since it is WAY out of my price range).

You can bait me all you want, but I specifically mentioned M193 in my reply, and you changed the stakes to mk262 (which very few people are going to be using).

brouhaha, I'm curious as to where you're getting the "Up to 50m of extra fragmentation threshold for M193" info from. Are you interpreting the data from the link below differently than me?

[url=http://groups.msn.com/TheMarylandAR15ShootersSite/rifleperformance.msnw]Barrel Length vs. Velocity & Fragmentation[/url]

DevL, IIRC, the only case I've read of where someone damaged their muzzle device was when an AR with a Phantom landed muzzle first. Here's a link to the thread:

[url=http://www.ar15.com/forums/topic.html?b=3&f=12&t=165389&w=searchPop]Phantom vs. Vortex thread[/url]

Look at the post by new-arguy at the bottom of the first page. Yes, this is the only account I've read where a muzzle attachment became damaged so while it's unlikely to happen it is still possible. I can understand why a permanently attached muzzle device doesn't bother some people. I just prefer to have that part be self-serviceable. Just my 2 cents.

The 16" 1:9 barrel is much more versatile than the 14.5" 1:7.  Ammunition selection alone leans more towards the 1:9.  But wtf do I know?

Did someone link Ammo-Oracle?  Ah...I see someone did.

No, I'm using different data.  Different temp/altitude/humidity and most likely the calculator is a different program.

[url]http://www.ammo-oracle.com/#fragrange[/url]

To me it's very practical to have a 16" barrel because I don't like having anything permanently welded to my barrel.  This makes upgrading and changing my config a lot easier.

The extra velocity may not add much but it sure doesn't detract from it either.

I also like the 1/7 twist because I will rarely if ever use anything lighter than 55 gr and I want to be able to step up to the Mk262 77gr good stuff as needed.[:D]

The best thing to do is decide what you want to do with your rifle and pick the best configuration for your needs.  

The 1/7 will do just fine with m193 too.  Though I do think the M193 at $170 per 1000 is a lot better deal than MK262 at $650 per 1000[BD].  Not that it's cost will stop me but for many it's a major consideration.

In my personal experience I've never felt that the extra inch was a hinderance when running CQB drills.  I also like to run my stock fully collapsed so that saves me more than 1 inch...[;)]

Ah, ok. I forgot to consult "the Oracle" [:)]. I've got a link for that sight but for some reason I usually go to the chart I listed first...probably because Forest has such an outstanding sight [:)] I'll have to remember the Ammo oracle for next time. And, now that I think of it, I used that very chart (from the Ammo Oracle) when I was making up my mind on a 14.5" vs. a 16".

While not all inclusive

[img]http://photos.ar15.com/ImageGallery/Attachments/DownloadAttach.asp?iImageUnq=17971[/img]

[img]http://photos.ar15.com/ImageGallery/Attachments/DownloadAttach.asp?iImageUnq=17972[/img]

[img]http://photos.ar15.com/ImageGallery/Attachments/DownloadAttach.asp?iImageUnq=17973[/img]

I will post the temp, alt etc when I figure out what it is in imperial as opposed to metric[;)].

Good thread!  I'm trying to decide whether to go 14.5 or 16 CHROMED this time.  I am leaning toward 1-9 for general use, mostly 55gr-68gr. Is there noticeably more muzzle flip with the 14.5" than with the 16"? (both having vortex FS)

No extra muzzle flip.  

Does anyone know what Horiuchi was shooting at Ruby Ridge or have any of the distances for shots fired?  Have we figured out what ammo the DC shooters used?

.308, 168 or 175 SMK I would bet.

Or you can look at it this way:

For 1.5 inches of barrel you get 1/3 of the way to 20in velocity.  (you are getting a better deal for that 1.5 inches than for the next 4inches.)

additional velocity counts. (That said the 14.5 in barrel is handy.)