16" vs. 20" AR-15 barrel?

[Jabronie]

I am putting together my first AR, I started out planning to do a carbon length for a short light weight rifle but I am putting quit a few higher end parts and wondered if I should be using a 20" barrel for better precision or Is there not much of a difference to the down range effects of a shorter barrel to a longer barrel for an AR?

for a reference here is my parts I am using
Defiance Machine match receiver set
JP silent capture buffer
JP LOMA carrier
JP high performance bolt
Timney Trigger

to be ordered a Lilja M4 barrel or 20" barrel

 

[YourAlterEgo]

Length won't have an effect on accuracy but it does effect velocity, which translates into effective range.

I would say it is a tradeoff between compactness vs range. I wish I would have gone with a 20" over the 16". Next build will be a 20".

 

[CASDB]

Go with a 16" with a midlength gas system. As your first this will allow you to multi-task the system and learn to employ it in multiple roles.

 

[Razor74]

Go with a 16" with a midlength gas system. As your first this will allow you to multi-task the system and learn to employ it in multiple roles.

+1 for CASDB
A lot of guys start out thinking they are going to do a lot of long distance shooting, and usually only wind up shooting 100-200yds max. They opt for the longer barrel and regret it later, 16" will do almost anything you need it to do.

 

[KUSA]

You should have both but start out with the 16.

 

[ORD]

+1 on the above.

Unless you just want to run the heavies (higher BCs) at higher MVs for use at extended ranges (~600+), then a 16-18" max barrel will do just about anything/everything that an AR was meant to do well.

Getting a QUALITY 16" barrel will achieve the levels of accuracy possible with a longer barrel, but as previously stated, you sacrifice max range for a lighter, more compact rifle. I too recommend the mid-length gas system on a 16" barrel as I have had excellent results from them over the last decade. The mid-length gas system will also operate smoother with the JP low mass operating system, and I also recommend an adjustable gas block to really fine-tune things.

 

[Kilmore]

HCS or Compass Lake 18" Stainless Steel Douglas barrel.

 

[jrob300]

+1 for CASDB
A lot of guys start out thinking they are going to do a lot of long distance shooting, and usually only wind up shooting 100-200yds max. They opt for the longer barrel and regret it later, 16" will do almost anything you need it to do.

This is my story. My 18" rifle length shoots very well past 600 with the 77's, but it's.... um..... boring... and too heavy and clumsy for non-LR work. Those little pills make me yawn. So it's getting rebuilt into a 16 middy to do what it was designed to do and a 20" 6mmAR or 6.5 Grendel will become my go to LR upper at some point.

John

 

[Jabronie]

I am sold, I will be going with the 16" mid length gas system

 

[Jabronie]

thanks for all your input

 

[WAYOFTHAGUN]

The 20 inch barrel is what was designed around the round so for its full potential 20 is better but 16 inches will get the job done. and better mobility.

 

[skinnj1]

thanks for all your input

Sounds like you have made your choice but from my experience contour plays as big a part as length. An old 20" sp1 colt is "handier" than many of the 14.5" pigs that some make. I turned/chambered a 6.5g barrel for my auto mechanic that was 18.5" and the final weight of the gun was less than 7.25 lbs minus optics/sling/ammo....personally, unless the rifle is set up for door kicking etc. I prefer extra length. If all you ever intend to shoot is paper, Bill Wylde proved a long time ago that little barrels can make little groups but if you are shooting reactive targets or game, little cartridges need help in the terminal ballistics department

 

[hewlett260]

Question and some food for thought? What do you see yourself realistically doing with it, and at what range? A consideration because, a ton of people that I know(but don't like to shoot with) like the longer barrel for velocity and yet don't really ever shoot the longer range. Accuracy isn't really a huge issue as ammo selection can bring either in tight. Remember the platform was never truly designed for ultimate precision, but as a combat rifle for us grunts who beat the shit out of everything we are given(that's why we can't have nice things). It fills the "precision role" pretty well but fills the "lay down accurate suppression while we maneuver role" exceptionally well. Coming from a military background and enthusiast trial and error, I have the 16" and my issue weapon is a 14.5". The only thing I wish my duty weapon had was a longer hand-guard with a free floated barrel and mid-length gas system. Longer barrel?, Hell no! Hope this helps.

 

[Jabronie]

to shoot 100-200 yards on paper and out to 400 on steal targets, I am not putting much into optics so I wouldn't expect to shoot much farther than that

 

[allidoiswin]

I am putting together my first AR, I started out planning to do a carbon length for a short light weight rifle but I am putting quit a few higher end parts and wondered if I should be using a 20" barrel for better precision or Is there not much of a difference to the down range effects of a shorter barrel to a longer barrel for an AR?

for a reference here is my parts I am using
Defiance Machine match receiver set
JP silent capture buffer
JP LOMA carrier
JP high performance bolt
Timney Trigger

to be ordered a Lilja M4 barrel or 20" barrel

14.5" barrel on an AR15 is all the length you will ever need. If you cant do it with a 14.5 you JUST CANT DO IT, anything else is just personal preference

 

[CASDB]

With a 14.5" barrel he'll be stuck pinning the compensator. Might as well stick with the 16" and leave room for modification down the road.

14.5" barrel on an AR15 is all the length you will ever need. If you cant do it with a 14.5 you JUST CANT DO IT, anything else is just personal preference

 

[skinnj1]

14.5" barrel on an AR15 is all the length you will ever need. If you cant do it with a 14.5 you JUST CANT DO IT, anything else is just personal preference

Wow, NRA high power is on real good reason for more than 14.5", so is trying to kill 140 class whitetails with a .300 "whateveryyouwanttocallTM" or explosive kills on a prairie dog with a .20 practical at longer ranges or easily staying above the minimum power factor in 3Gun competition in all conditions.Ar's can fill a lot of roles, limiting one's self to 14.5" in all situations is hardly prudent, I could just as easily say "all anyone needs is a single shot .22 and a 30-30" and for some that would be true but it doesn't makes it true for everyone....

 

[BoilerUP]

Went through the same dilemma about a year ago, and settled on 18" rifle gas as a compromise. In the end, a 16" middy would have worked fine for my purposes and been a bit lighter/handier, but the extra couple inches worth of velocity was nice when shooting 77s @ 2660fps to 900yd this past weekend.