AR 15 bbl length questions???

[Alfonso]

I am going to be buying an AR15 finally. But I have a question about barrel length. I think I will be getting the RRA A2 or A4 or Car. I was looking at the mid size A2 too. Which bbl length is preferred, 16" or 20" combined with which hand guard?

Thanks

 

[Blackthorne]

I just went through this so let me impart the wisdom that was imarted to me, and let anyone correct my mistakes or add details.

While the shorter barrels surely do look cooler, the 16" seems to be the "middle ground" btween shortness (lighter and easier to move around in cramped conditions) and length (for higher muzzle velocity and acuracy). Keep in mind that most ARs work at 200 or less and most agree the 10.5 to 14.5 barels are fine at these ranges.

The beauty of the platform is that you can get the 16" upper with no hassel from a retailer, then pick up any other length you like as a complete upper and switch them at will.

Note that Colt doesn't transition well to anything but Colt, but you were talking RRA so you should fine with any upper EXCEPT Colt.

There is also a 22 complete upper for under $300 that will let you take it to most rimfire ranges.

Fore ends are for grabbing onto and hanging stuff from.

If you intend to hand alot of stuff off it, or are really striving for accuracy and an longer upper lifespan, a "free floating" foregrip is the way to go. It attaches to the upper reciever and removes all contact with the barrel making for improved accuracy and longer componet life in the upper as it reduces stress and alignment issues.

If you are not going to hang furniture of it, the stock one should be fine. Or you can get non free floating railed front ends that go on with the D ring without any changes, they just replace the stock ones with no hassels. Surefire makes a few great ones.

If you want free floating you are stuck with rails, as I haven't seen any FF foregrips that aren't Picatinny.

Of course, the Picatinny rails look great bare or with covers

 

[JNG]

I prefer 16". The longest I shoot is 300yds but mostly less than 100yds. 16" is just fine for those distances. Mine has the Carbine length handguard. If you are not going to use any optics think about going with one of RRA's midlength 16 AR's. There is more distance between the front and rear sight which is a good thing when using iron sights. If you are mostly going to use optics then the carbine length is fine.

 

[canucklehead]

14.5" looks the coolest, in my opinion.... like mentioned above, the 'average' user in a non-combat scenario will likely see little accuracy/range difference between standard lengths.

 

[Hitzy]

Get a 14.5......16" is bastardised version for american civie sales......

 

[dangertree]

Get a 14.5......16" is bastardised version for american civie sales......

So thats why Diemaco went with 16" for the SFW. The American Civvie sales.

 

[Hitzy]

So thats why Diemaco went with 16" for the SFW. The American Civvie sales.

Is there a 16" M4 issued to any military, anywhere in the world?

 

[NaOH]

My 14.5" used to hit the 500m clanger 4 out of 5 all day long with my ELCAN (when I still had a 500m range).

Of course HeliDoc would show me up by doing it standing unsupported.

 

[dangertree]

Yes. There is an issue C8 in 16", the C8SFW. (Photo Reg CC).

Why 16"?

From the oracle...

[FONT=Times New Roman, Times, serif]Q. At what range will M193 fragment? How about M855?[/FONT] [FONT=Times New Roman, Times, serif]Assuming true M193 or M855 ammo, velocity is the key. Velocity is dependent on barrel length and environmental conditions.[/FONT]
[FONT=Times New Roman, Times, serif]As barrel length increases, the bullet is propelled faster by the expanding gasses in the barrel, imparting more velocity on the bullet, resulting in a longer range before a fired bullet drops below 2700 fps. A shorter barrel imparts less velocity, and therefore the bullet has less range.[/FONT]
[FONT=Times New Roman, Times, serif]Temperature, altitude and humidity are other factors. As temperature or altitude increases, air becomes less dense and bullets travel faster. Contrary to common conceptions, as humidity increases air also becomes less dense and helps bullets retain velocity.[/FONT]
[FONT=Times New Roman, Times, serif]It is important, then, to keep in mind that any statistics given can only be approximate and can be affected by a wide range of factors. But as a baseline, these numbers are what you could expect for 75° F, 25% humidity, at sea level, from various barrel lengths:[/FONT]
Distance to 2700 fps
20" Barrel
16" Barrel
14.5" Barrel
11.5" Barrel
M193
190-200m
140-150m
95-100m
40-45m
M855
140-150m
90-95m
45-50m
12-15m
[FONT=Times New Roman, Times, serif]As you can see, barrel length and ammo selection make a major impact on fragmentation range.[/FONT]

14.5" and 11.5" barrels are great, why waste all that weight and effort lugging around something larger?:
Shorter barrels are critical to close quarters battle (CQB) and urban work. Here ranges are shorter and getting that barrel around corners and inside houses is tough enough without it being too long. All that velocity isn't necessary and I'm worried about overpenetration anyhow so it's a good thing to keep it under control. If I really am worried about low velocities I'll just switch to controlled expansion rounds.
I wouldn't be seen with anything shorter than a 16" and I'd try to hide my face if friends saw me without a 20":
I need a more flexible weapon that allows me to get out to 200 meters when I have to. Additionally, fragmentation is critical to my philosophy about wound ballistics and I want as much of it as I can get. This means at least 16" on my barrels and 20" is better. 16" is plenty short enough for interior and urban work and it gives me the advantage of not having to worry about using my rifle for long shots on deer or for longer defensive engagements. Plus, if I had a true 14.5" barrel I'd just have to register it with the ATF as a short barreled weapon anyhow. Why should I have 16" of overall length and only get the benefit of 14.5" of that?

Summary, An extra 40-50m of fragmentation velocity envelope for 1.5" extra barrel length. From 100m to 150m.

For user convenience more than mixed up fighting , or out to 100m, I'd want a 14.5". Handy getting in and out of vehicles, and more versitile than a 10.5". In my world now I do shoot a 14.5" for instinctive shooting paper punching and bouncing pop bottles. (I have to fight wanting to shoot it from the hip.)

My only proper deployment I carried what everyone carried, a 20" C7A1. Solid rifle, and really, the best shooter for the reasons above. The few times I did get to carry a C8, I was between 14%-19% cooler than everyone else, and as always for fast shooting, preferred the iron sights.

Anyone deploying/deployed/back want to comment on your fantasy sect/pl barrel length ratio? Assuming available 10.5", 14.5", 16" and 20" barrels. MGs aside.

I'd be interested from combat arms, what they would carry if they had a choice.

Police in Canada can buy what they want, they're by and large going with 16"ers.

Cheers,
DT


PS: As I'm typing this, on the news, I'm sure I'm seeing Pats in Afghanistan fighting with 16" carbines. How common are these?

 

[KevinB]

I had a SFW when I was here with the forces.

All the new C8 purchases are the 16" version as opposed to the 14.5"

As Dangertree mentioned the CF has the 16" carbine gas system and so does the British SAS (and other SOF units in the UK)

Personally I prefer the 16" midlength.