18" vs 20"

[Blazer11]

Im new to this site and starting my first build. I'm building this gun for deer hunting mainly maybe some elk. I'm stuck on what size barrel to get. Is the extra 2 inches worth the weight? Just looking for some help.

[imschur]

I'll vote no unless you are shooting extreme distances

[Jgun]

At what range do you intend your longest shots to be?

[unforgiven]

Welcome from Indiana brother Blazer.More is good IMO. <dontknow>

[Blazer11]

Hopefully no more then 450 yards but who knows when you have one in your sights.

[98Z5V]

You could rock a 16" barrel to 500 with ease.  <thumbsup>

[mantawolf]

Only makes about 90fps difference. I went with a 16"

[Slash]

This is always a controversial topic, but here is my opinion:

16" - 400 yards

18" - 600 yards

For longer ranges I would want a 21-22" barrel.

I firmly believe that 18" is nearly ideal for most .308 applications.  VERY, VERY few guys ever shoot past 300 yards, and even fewer go past 500 yards.  18" is the perfect compromise of weight, muzzle velocity and ergonomics (have you ever tried toting an AR with a 24" barrel through the woods?).

[Robocop1051]

The US military is confirming kills out to 1200 yards with a 20" barrel... 16"-18" is plenty for anything I ever plan on doing.

[planeflyer21]

There is a guy on another forum, who goes to the local "high power" matches at his club and uses his Marlin 1894C in .357 Magnum.  He consistently does well against the .223 crowd.

For those tuning the load to their barrel length with handloading, you should be able to find a more suitable powder for more suitable power out of 16" and still retain more than acceptable performance for long-er distances.

Jon

[survivalshop]

16 " HB , short stiff barrel for best accuracy out to mid ranges .

For hunting the short bbl. rules & the 16" HB I have is only about 2 oz. heaver than an 18" light weight .

[cz777]

This is always a controversial topic, but here is my opinion:

16" - 400 yards

18" - 600 yards

For longer ranges I would want a 21-22" barrel.

I firmly believe that 18" is nearly ideal for most .308 applications.  VERY, VERY few guys ever shoot past 300 yards, and even fewer go past 500 yards.  18" is the perfect compromise of weight, muzzle velocity and ergonomics (have you ever tried toting an AR with a 24" barrel through the woods?).

hate to say this but bump the yardage to 200 yards to each given range so 18'' is the over-all sweet spot ....you can do all of 800 yards easy and push to 1000 with 175 VLD ...of course the scope too 

[ThBrtmn]

The US military is confirming kills out to 1200 yards with a 20" barrel... 16"-18" is plenty for anything I ever plan on doing.

Just to clarify is that with the semi auto AR platform or Bolt?

[tolbndfishin]

M110.  KAC-produced 308 with a 20"  semi-heavy barrel.  The profile is .875" at the gas block, not .936" as with true heavy barrels.

I just bought a krieger in this contour, but havent assembled yet to shoot, only to check fitting of everything.  I consider it a bit heavy for a hunting rifle barrel, but isn't unbearable.  Lugging it through rough terrain i might think different, although that isnt the primary purpose for this rifle, so no worries.

Russ

[jeffreyC]

Watching Magpul's Art of the Precision Rifle, Todd Hodnett is saying that 16", or 18" or 20" makes no real difference, all will work to 1,000 yards.

Makes me reconsider a longer barrel, maybe I will just get a lighter one instead.

[washguy]

Watching Magpul's Art of the Precision Rifle, Todd Hodnett is saying that 16", or 18" or 20" makes no real difference, all will work to 1,000 yards.

Makes me reconsider a longer barrel, maybe I will just get a lighter one instead.

Jeffrey  now your on the right track  my 16inch will smack moa steel at 500  and its easy to carry  wash

[unforgiven]

Watching the Military channel,Marine sniper one of the instructors I think mentioned they would wind up going to 20" barrel w/1-10 twist.

[MaDuce]

I'm no expert but based on what I have read from people who've extensively tested these barrels, the real difference between the two lengths is not what distance you're shooting at but what kind of ammo you're putting through it. Standard and light loads from what I've read peak at 20 inch barrel, but an 18 inch barrel launches them at typically 20 to 70fps slower. In other words, you can probably throw the bullet at the speeds that make up the difference. Not worth the extra size and weight, hence why 18 inch barrels are so popular.

However, heavier loads require longer barrels for maximum performance, peaking at 24 or 26 inch (I can't remember which. However, most of the heavier loads peak in a 20 to 22 inch barrel and most of the ones that peak in longer barrels; like the 18 and 20 incher relationship, get very little boost.

However, loads that peak in an 18 or 20 inch barrel start to slow down in a 24 or 26, while 20 inch barrels don't impair them at all.

In short, 18 inch is the ideal barrel length for light and standard loads. But for the absolute maximum in load versatility across the board, go with 20.

I myself went with 20, but an 18 incher wouldn't have bothered me.

[pridekills]

http://www.tacticaloperations.com/SWATbarrel/

The above link has provided me with the best experiment I have found on barrel length for a 168gr .308.  Hopefully it proves useful to all of you also.

"During the development of the Tango 51, Tac Ops took a standard 26-inch barrel and cut it down to 18 inches in one-inch increments.  Between 10 to 20 rounds were fired at each invrement.  They found that a 20-inch barrel provides for a complete propellant burn and no velocity loss when using Federal Match 168-grain BTHP, a cartridge that has become something of a law enforcement standard.  Going to an 18-inch barrel only resulted in a loss of 32 feet per second (fps). "

Per Federal's data, the muzzle velocity in 2650fps, this would mean 2618fps out of an 18" bolt gun.  If someone could verify the speed out of an 18" or a 20" AR, I would be appreciate it.  With current powders, you could reload a 168gr SMK with CFE223 up to 2828fps.  Rather that load is accurate in your rifle is another story though...

I'm building my first rifle, and with the research, I'm sticking with an 18" barrel for a 600yd hunting and high power rifle.

[Robocop1051]

That's a great link <thumbsup>

It has been posted several times over the years, but its always a good read.

My .308 is a 17" heavy barrel (.875@GB). I'll bet I'm still at 2600fps with factory 168gr.

[StainTrain]

That sounds about right.  When I get my Magneto Speed back I will verify.  My service sniper rifle (24)  is 2667 with a 5 deviation, and my personal (18) is 2635 with a deviation of 7.  As you can see the difference isn't as much as the sub-moa Internet shooters would lead you to believe.

My figures are out of the same lot of ammo. It will vary now since we switched lots.

[Ben Diss]

Another to consider is that a 20" barrel will likely take a rifle length gas system, a 18" will likely take a mid-length and a 16" will take a carbine length gas system.  There are some advantages to the longer gas system.

[Robocop1051]

Another to consider is that a 20" barrel will likely take a rifle length gas system, a 18" will likely take a mid-length and a 16" will take a carbine length gas system.  There are some advantages to the longer gas system.

While those are the most common configurations, you can have a rifle length gas system on a barrel as short as 16".

My 17" has a rifle length gas system. Fulton Armory used to make a 16" barrel as a regular option.

[unforgiven]

I have a 14.7 w/mid lenght gas that has performed flawleassly.Just my 2 mags.

[Rsquared]

For what it's worth. My Armalite's use a mid-length on the 16" barrels and they perform pretty well. Granted, I use adjustable blocks on all of mine.