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Page AR-15 » AR Discussions
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Posted: 4/13/2006 5:48:40 AM EDT
In building my SHTF rifle, I had trouble deciding whether to use my SBR registered lower and go with a 11.5" barrel, or a more traditional 16" barrel.  I am planning on having a supressor for this gun, and attached to the end of the 16" makes it very combersome for manuvers, and very front heavy.  However, the 11.5" barrel does not have a reliable accuracy (at my skill level) past 350yds.  So, I started wondering  - DOes anyone make a barrel extension which threads onto a barrel to increade the otherall length?  Granted, I know there wouldnt be as much barrel uniformity, and the accuracy wouldnt compare to a standard barrel, but it would still offer some benefit, and would be a lot lighter and more manageable than carrying around an entire extra upper, not to mention easier and faster to attach.  Can Anyone help?
Link Posted: 4/13/2006 6:00:11 AM EDT
[#1]
Link Posted: 4/13/2006 6:41:26 AM EDT
[#2]
When you suppress that 11.5, it will give you a mild increase in velocity from free bore boost, but not velocities like a longer barrel would have. For years, American troops have carried 20" M16 rifles. Yeah, their cumbersome when compared to an M4, but for an all around rifle they are pretty good.

If you're going to carry two weapons (or two uppers perhaps) yo umay be better suited with a nice 12 gage pump action as an addition to a 16, 18, or 20" AR.  Just a thought.
Link Posted: 4/13/2006 6:43:53 AM EDT
[#3]

Quoted:
However, the 11.5" barrel does not have a reliable accuracy (at my skill level) past 350yds.  ....  Can Anyone help?



It's not the rifle - it's the shooter.

#1 way to improve your range - practice.

#2 if get your skills up to it, then the ability to see better helps - think Compact ACOG or TA31.

#3 WHY would you ever need to shoot 350 yards in a realistic situation?  The only way you'll hit anything at that range is if they are just standing out in the open.  How is that a threat to you?
Link Posted: 4/13/2006 7:27:33 AM EDT
[#4]
good points, if you are preparing a rifle for a shtf situation, then you need to be more than just adaquate with your training, you need to be spot on or damn close to it.
Link Posted: 4/13/2006 10:01:57 AM EDT
[#5]

Quoted:
In reguards to your application, there is no muzzle device that would significantly increase velocity/accuracy when attached (thus giving the barrel two different personalities).



I do not mean some sort of flash hider or muzzle break, I am thinking about a muzzle device that is married up to the barrel, has the same rifling, and gives you an extra 8-10" of barrel length with no additional escape of gas or power.


Quoted:
If you're going to carry two weapons (or two uppers perhaps) yo umay be better suited with a nice 12 gage pump action as an addition to a 16, 18, or 20" AR.  Just a thought.



I already have a real nice 6" Serbu Super Shorty Maverick Shotgun AOW awaiting transfer approval, for just this type of application.


Quoted:
#2 if get your skills up to it, then the ability to see better helps - think Compact ACOG or TA31.



I am working with a TA31F.
Link Posted: 4/13/2006 10:27:36 AM EDT
[#6]
FYI lengthening the barrel would only get you more MV - the only difference being in HOW MUCH you have to adjust for drop and wind, you'll still have to adjust for them.  Actual group size will not appreciably change.

However if you want the ability to change barrel length there are some options.
1) LMT Monolithic upper (and other similar units comming out by other manufacturers)

2) MGI Upper that uses standard barrels - that you can change out by throwing two levers.  www.mgimilitary.com/qcb.htm
Link Posted: 4/13/2006 12:54:39 PM EDT
[#7]

Quoted:
FYI lengthening the barrel would only get you more MV - the only difference being in HOW MUCH you have to adjust for drop and wind, you'll still have to adjust for them.  Actual group size will not appreciably change.



I was under the impression that having the bullet spiraled by the the rifling twist for a longer period of time would result in a more consistant flight path, and therefore, better accuracy.
Link Posted: 4/13/2006 1:00:05 PM EDT
[#8]

Quoted:
I was under the impression that having the bullet spiraled by the the rifling twist for a longer period of time would result in a more consistant flight path, and therefore, better accuracy.


Nope, Once it's spun up it's stabil.

Shorter barrels have an advantage in less barrel whip, which helps in accuracy.
Link Posted: 4/13/2006 1:37:40 PM EDT
[#9]
So, am I to understand that the concept of a longer barrel meaning more accuracy is a myth?

Link Posted: 4/13/2006 1:42:29 PM EDT
[#10]
Link Posted: 4/13/2006 1:45:06 PM EDT
[#11]
The only thing a longer barrel provides is more velocity.  The higher the velocity, the more the bullet fragments at longer ranges, thats why our troops carry M16A4's instead of some 11.5" shorty.  The longer the barrel, the farther the terminal range of the bullet.  If its an SHTF gun then don't plan on long-range shooting and just practice a lot.
Link Posted: 4/13/2006 2:14:30 PM EDT
[#12]


Quoted:
So, am I to understand that the concept of a longer barrel meaning more accuracy is a myth?





haveing a longer Bbl gives you a longer length between sights and that gives you more accuracy, so if you want a shorter Bbl but better accuracy useing iron sights get a dissy.
Link Posted: 4/13/2006 3:06:29 PM EDT
[#13]
Sight radius is true enough, but only for irons and BUIS. For an EOTech or other sight it has little effect.

A longer bbl does give more velocity but once the bullet is into the bore it doesn't slip past the rifling at all as far as I know, meaning that after the first inch or so it's turning as fast as it will be turning when it exits.

There may be merit to the theory that having it travel, controlled in the bore, will stabilize it more but I don't think it has enough effect to merit it.

The low velocity / non-fragmentation issue has been overcome with proper ammunition and of course, shot placement (nerve vs. hydraulic shots.)

A 14.5 inch bbl will not shoot as accurately at 700 yards as will say... a 20" bbl. Once the velocity goes subsonic the bullet tends to be unpredictable, in my experience.
Link Posted: 4/13/2006 3:11:35 PM EDT
[#14]

Quoted:
A barrel extention attaches to the chamber end of the barrel.  I think you are referencing a muzzle device.  
In reguards to your application, there is no muzzle device that would significantly increase velocity/accuracy when attached (thus giving the barrel two different personalities).

In a personal defense situation, I don't forsee the probability of taking shots at the 350m range.  If you did have to, you would have plenty of time to swap uppers or rifles or just grab a 308.


+1
Link Posted: 4/13/2006 5:33:36 PM EDT
[#15]
So, ballistically speaking, an H.S. Precision Pro-2000 pistol in .308 with a 6" barrel is just as accurate as a 26" barreled H.S. Precision Rifle in the same caliber?
Link Posted: 4/13/2006 6:47:38 PM EDT
[#16]

Quoted:
So, ballistically speaking, an H.S. Precision Pro-2000 pistol in .308 with a 6" barrel is just as accurate as a 26" barreled H.S. Precision Rifle in the same caliber?


You can have arguments from any side, but here is my take on barrel length and accuracy - you can only cut a barrel back so far before MV drops off, the ES and SD for MV's change drastically, and unburned powder becomes a factor.  At long ranges higher MV's will give you the ability to keep the bullet supersonic for a longer period of time.  Do you wonder why most people don't try to shoot 16" barrels at 1000yds?

Link Posted: 4/13/2006 6:52:52 PM EDT
[#17]
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