Max effective range from 16 and 18 in barrel

[chriss1727]

I want to know what the effective range out of a 16in and 18 barrel are. I have read up on accuracy but that not what I need. I'm asking what range will impacy velocity still be enough to do damage. I am close to picking up LR308 with a 16 or 18 in barrel. Everyone on here has givin out alot of good info so far and just want to thank everyone for it.

[SWshooter]

There isn't enough difference between a 16 and 18 in. barrel to tell. You'll probably see more difference between loads, especially bullet weight. What are you planning to shoot and how far away do you want to shoot it?

[chriss1727]

I would like to be around 500yds maybe 600yds for my max kill range with the shortest barrel. I've looked at some ballistic tables from ammo companies but they all test out of 20-24 in barrels. I know I'll lose some enegy from the shorter barre=less burn. For close range I want to use the 150-155gr? for distance I should use the 160-168gr? I am converting from dirt bikes to shooting for my hobby so be patient with me if I am asking stupid questions.

[TacBlade]

Hey!  There are no stupid questions!  I have been into guns my whole life and I would like to know the same thing, as I am building one right now.  I just cannot figure out to go with 16" or 18" either, and what the effect is going to be with going with a carbine gas tube rather than a Mid or full length gas tube? I need answers also. Thanks

[lynxpilot]

Bullet stability drops rapidly as you approach the speed of sound.  At sea level on a 'standard' day, that is 1,116.4 fps.  A fair measure of the maximum range of any given load is when it goes subsonic.  You can estimate this range using any one of a bunch of online ballistic caluculators so long as you know muzzle velocity (requires chronograph), ballistic coefficient (varies depending on muzzle velocity but is normally provided for standard velocities by bullet mfgr.), and atmospheric data where you are shooting (like temperature, humidity, and altitude in mean sea level).

You can estimate a lot of those and still stay within a reasonable range of accuracy to decide whether or not the barrel length you are looking at will suffice.  Case in point, I bought a DPMS LR308-AP4 which comes with a 16" carbine barrel.  My loads chronographed consistently 200 to 250 fps less than the identical load from my loading manual, which gives data taken from a universal test mount at barrel length 24".  At 8" difference and the speed differences I mentioned from my barrel, you could surmise that the shorter barrels will produce about 30 fps less per inch of barrel.

If you don't chrono your rounds, use what data you have available.  If you reload, it's what the manual says minus the difference for barrel length, or if you use factory loads, use what the box says minus the correction for barrel length.  Bullet manufacturer should provide ballistic coefficient or you can google it.  Plug this data into one of the online ballistic calculators and see where the round goes subsonic (less than 1,116.4 fps).  The calculator will also give you the energy of the bullet at that speed, so you can get an idea of its effectiveness.  That's your effective range.

[chriss1727]

LOL. I was doing homework for college algebra class when I read this. I wonder if I can get extra credit for working this out.

x=(Iv)-[(24-BL)*30fps]      fx > 1116.4  (going with horndy 165 gr. BTSP InterLock @ 600yrds)

16in barrel

x =(1615fps)-[(24-16)*30fps]

x = 1615 - (240)

x = 1375 fps impact velocity

18in barrel

x = 1615-[(24-18)*30]

x = 1615-180

x = 1435fps

since its still supersonic I should be good out to 600yds with both right? will this be enough for wild boar in texas?

<dontknow>

[chriss1727]

I'm retarded you just ment put the (muzzel velocity - 30fps per less inch) into the calculator and they give you the info. 

Army mentality work harder not smarter.  :o

The 16 still came out 1436fps and 755ft-lbs @ 600 yrds so same questions. Will it will be reasonably accurate and have enough energy to take down a good size zombie.... I mean wild hog?

Trajectory (200 yd. zero) -109.1 @600yrds

Come Up in MOA 17.4

another question was,  I was wanting to get the nightforce NXS 2.5-10x32 scope with the velocity reticle. I am willing to spend alot on a good optic so I'll take any sugestions on optics that can take abuse and keep zero @ 600yrds.

[survivalshop]

You will have no problem having enough energy to down game, or humans for that matter, out to 600 yrds.

There have been confermed kills on humans out past 1000 yrds. ,but most give 800 yrds as effective range for the 308/762x51.

Of course at those ranges , is all with the right bullet, rifle , optics & the most important , the shooter .

Next year I will be taking my 16 & 20 " to a 500 yr. range ,just to see what the 16 " will do as far as accuracy .

I have no doubt at all the bullets will perform out that far .( as long as you can hit what your aiming for .

As said above , there is not much difference between 18 & 16" barrels . There's a bunch of people shooting 16" out that far.

[SWshooter]

The generally excepted minimum energy levels for a clean kill on game call for 1,000 foot pounds energy (fpe) for deer sized game and 1500 fpe for game in the range of elk. I always thought people were a little easier than deer, so figure about 750 for people, especially since we're looking at a stop, not necessarily a kill. If I were keeping my shots within 300 yds I would feel confident with the 150 gr bullets, for ranges out to 600 I would like the 168-180 gr bullets better. The one unchanging variable in ballistics is bullet weight, no matter haw far it travels, it always arrives with the same weight. The bigger the caliber, and the heavier the bullet, the better the penetration will be.

[Robocop1051]

A while back, Imschur posted a link here to an article about shorter barrels.

I have since emailed that same link to a LOT of people.

[randybill]

after reading that article i'm gonna go with an 18" barrel for my Lr308 build.  SASS upper here i come!  now i need to decide on a trigger....

[TraderJack]

When I was growing up(about 100 years ago...) the maximum, effective, humane, 'kill shot' was to be taken at no more than 300 yds.  Of course, now, with better gear, that has been changed considerably, to nearly 400 yds.

My point is that if a 'humane' attempted shot is seen to have a max range of 400 yds, why wouldn't this apply to either a 16" or 18" bbl?

The ballistics would be a non factor...

Just sayin...

[DocLarsen]

TraderJack,

I believe the 300 (now 400) yds. is based on an average hunter's ability to place a shot in a paper plate sized ring around the vitals and not the gun's/projectile's ability to inflict a humane shot.

If you ever get a chance to check out a TV show called The Best of the West (I think it is that or something very similar), you'll see guys who practice long range ethical hunting in areas where you just can't get within 3-400 yards of a game animal.

DocLarsen

[TraderJack]

Thanks Doc,

Yeah, I've seen the show... and I understand your point - That most long range shooters are 'not average'.

That being said, my point was sort of round-a-bout... (remember the  Noyeki Commanche?).  - Why would a 'non-average', long range qualified shooter be concerned about the performance characteristics of the 16" vs. the 18" bbl?

To my mind, this is just a point of curiosity... and general information.  But, for practical applications...?  Isn't the qualitative difference very minimal?

Best Regards,

TJ

[Brenten]

First post on this forum. I like it so far. 

I have chrono'd loads out of a 16 inch and a 22 inch barrel and I was shocked at the difference in velocity being so little.  The long barrel velocity was 2730 something fps and my 16 was 2620 something(don't remember the exact numbers as it was some time ago).  I called Federal or winchester(can't remember which) about this and they indicated that 308 goes full burn by 15.5 inches or so.  If you are under that, you loose lots of velocity.  if you are over that you gain but not as much. The guns were a DSA FAL 16 inch, and an M1A.  I have heard from other sources that 308 does complete burn by 16.5, so it is very close. 

here is an article:

http://www.chuckhawks.com/rifle_barrel.htm

[TacBlade]

Welcome!!! Welcome!!! Welcome!!!  We like new members!!!

[Brenten]

Thanks.  I am a newbie to the Ar10 world, but not a newbie to AR's.  As for 308's, I come from mostly M1A/M14 background having owned about 19 total at one point.  Most are gone and only a few left.  Have also had HK-91(in the form of the SAR-8 original) and FAL's. 

[J.Boyette]

I want to know what the effective range out of a 16in and 18 barrel are. I have read up on accuracy but that not what I need. I'm asking what range will impacy velocity still be enough to do damage. I am close to picking up LR308 with a 16 or 18 in barrel. Everyone on here has givin out alot of good info so far and just want to thank everyone for it.

I think that a 16" .308win is about 700yds for first round hits with limited training. If you know how to run a rifle, 800yds with a 16" for first round hits and keeping the shots at about 1 MOA to 1.5 MOA groups. 

[TacBlade]

My 16" was tested and it is 1 coyote-OA at 300 yards!!!  That is all I need!!!