Precision AR barrel length?

[mkm]

I already have my cqb rifle up and running.  To me, it's set up more for combat accuracy at 100 yards +/- and not much precision at farther distances.  That's how I want it.  Now, it's time to start thinking about my next project once the budget allows for it.

I'm thinking about building an ar designed for precision at longer distances 200 +/-.  It'll be set up primarily for bench/prone shooting; therefore, I'm not overly concerned about weight and maneuverability.  What length barrel would you recommend and why?  I'm leaning toward 20", but is the extra length really worth it?  I'm fairly confident that my current 16" would group nicely if my rifle was scoped.  I'm also open to suggestions about other components, but barrel length is my primary question.


I know there are better rifles and calibers for precision distance shooting; that is not what I'm here to discuss.  I'm concentrating on the ar-15 platform because it allows me to concentrate on stocking one caliber/magazine type, I like consistancy in functionality of my self-defense weapons, and I like the speed of a semi-auto for this application.  I also have a bolt action hunting rifle to fall back on if needed.

[Big Frank]

Why not a 24" barrel?

[mkm]

Why not a 24" barrel?

No reason.  No length is off the table at the moment.  I'm, mainly, looking for pros and cons of different lengths.  Would the extra length of a 24" be that much more beneficial?

[tombogan03884]

I've seen guys shoot 10 out of 10 bullseyes at 500 meters with a standard (20 inch) M-16.
I don't see why a good 20 inch bull barrel would not do the trick.
Standard ammo is designed for 16 -20 inch barrels custom ammo with slower powder may give even better accuracy, but if you go longer than 20 inches using standard ammo you may lose velocity as the powder burns out before the bullet exits the barrel.

[Respen33]

I've seen guys shoot 10 out of 10 bullseyes at 500 meters with a standard (20 inch) M-16.
I don't see why a good 20 inch bull barrel would not do the trick.
Standard ammo is designed for 16 -20 inch barrels custom ammo with slower powder may give even better accuracy, but if you go longer than 20 inches using standard ammo you may lose velocity as the powder burns out before the bullet exits the barrel.

If you are looking to build something i would go with 20". As said above most stock rounds are geared to this. Here is food for thought though, are you looking to get your hands dirty building it or just looking for suggestions on where to go? If its the later then check this out:

[url]http://www.lwrci.com/p-120-repr.aspx#inf-tabs/url]

the R.E.P.R from LWRC arguably is the best AR platform 7.62 that you can carry. You can change from semi-auto combat to "bolt action" like single round to increase accuracy. This is my DREAM 7.62 platform. Why carry a long rifle and an AR when you can have both? BTW it comes in 16" barrel or 20". i would go 20" for Accuracy.

[Sponsor]

[Big Frank]

I've seen guys shoot 10 out of 10 bullseyes at 500 meters with a standard (20 inch) M-16.
I don't see why a good 20 inch bull barrel would not do the trick.
Standard ammo is designed for 16 -20 inch barrels custom ammo with slower powder may give even better accuracy, but if you go longer than 20 inches using standard ammo you may lose velocity as the powder burns out before the bullet exits the barrel.

If the powder all burned up before the bullet exited the barrel they wouldn't need flash hiders. And it would take a barrel several feet long to lose velocity.

[mkm]

What about the increased effects of movement from recoil, wiggles, etc. of a bullet being in a longer barrel for more time. Will a free float tube makes those effects negligible?

I'm also not interested in custom loads at this time. It would be all factory.

[MikeBjerum]

The "big boys" shoot full floated 24" bull barrels with target crown - no fluting, no threaded muzzles!  I have shot a few of them, and the accuracy is far beyond my capabilities, but I noticed large increase over my 20".

Many even epoxy a tube on the barrel that increases the sight radius by another 2" to 4".

[tombogan03884]

The "big boys" shoot full floated 24" bull barrels with target crown - no fluting, no threaded muzzles!  I have shot a few of them, and the accuracy is far beyond my capabilities, but I noticed large increase over my 20".

Many even epoxy a tube on the barrel that increases the sight radius by another 2" to 4".

Won't have any effect on a scoped rifle.

[MikeBjerum]

Won't have any effect on a scoped rifle.

If you shoot a scoped game you are correct.  However, ...