The Down Range Forum

Member Section => Tactical Rifle & Carbine => Topic started by: mkm on November 13, 2012, 09:56:23 PM

Title: Precision AR barrel length?
Post by: mkm on November 13, 2012, 09:56:23 PM
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.
Title: Re: Precision AR barrel length?
Post by: Big Frank on November 13, 2012, 10:11:20 PM
Why not a 24" barrel?
Title: Re: Precision AR barrel length?
Post by: mkm on November 13, 2012, 10:15:59 PM
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?
Title: Re: Precision AR barrel length?
Post by: tombogan03884 on November 13, 2012, 10:31:51 PM
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.
Title: Re: Precision AR barrel length?
Post by: Respen33 on November 14, 2012, 09:47:23 AM
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.
Title: Re: Precision AR barrel length?
Post by: Big Frank on November 14, 2012, 08:41:05 PM
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.
Title: Re: Precision AR barrel length?
Post by: mkm on November 15, 2012, 05:23:03 AM
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.
Title: Re: Precision AR barrel length?
Post by: MikeBjerum on November 15, 2012, 09:05:01 AM
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".
Title: Re: Precision AR barrel length?
Post by: tombogan03884 on November 15, 2012, 09:43:34 AM
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.
Title: Re: Precision AR barrel length?
Post by: MikeBjerum on November 15, 2012, 10:56:41 AM
Won't have any effect on a scoped rifle.

If you shoot a scoped game you are correct.  However, ...
Title: Re: Precision AR barrel length?
Post by: Solus on November 15, 2012, 12:10:20 PM
Quote from: Respen33 link=topic=21000.msg263383#msg263383 date=1352908043

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

[/quote
Title: Re: Precision AR barrel length?
Post by: PegLeg45 on November 15, 2012, 03:35:25 PM
F-Class Tactical shooters and service rifle shooters shoot the AR out to 600 yards.

Like M58 posted, a 24" bull barrel with twist rate matched to bullet weight (those I have spoke directly to prefer 70-something weight and up for that distance), loaded with the right burn-rate of powder and you can do some real tight shooting.
Title: Re: Precision AR barrel length?
Post by: fightingquaker13 on November 15, 2012, 10:54:46 PM
I'd get it in 1 in 7 twist to handle heavier bullets at longer ranges. Between the 20"-22" (probably my choice) and 24" I couldn't say. What I would say is that you want a free float handguard, as without a free floated barrel you're pissing money away.   Which ever route you go it won't be cheap. Don't skimp on the handguards, the glass or the trigger. Good luck.