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View Full Version : how much velocity do you loose with a 14.5" barrel?


Roo
11-06-2007, 12:17 PM
instead of lets say 16" ? how much distance would you say you loose having a 14.5 over a 16?

PIRATE14
11-06-2007, 12:19 PM
instead of lets say 16" ? how much distance would you say you loose having a 14.5 over a 16?


Not enough to make much of a difference...........

That's my smart *** answer for the day..............:43::chris:

odysseus
11-06-2007, 12:21 PM
Check ARF, I recall someone had posted chrono's and a table of velocities of 5.56 from various barrel lengths.

FreedomIsNotFree
11-06-2007, 12:23 PM
Not enough to make much of a difference...........

That's my smart *** answer for the day..............:43::chris:

I got one better....

This thread is longer than the distance you will lose...

4 Brigada
11-06-2007, 12:26 PM
I think if the question was compared to a 20 match barrel it would be more significant, I watched local SWAT at the range were I shoot with their brand new Uncle Sam handme down M4's couldnt hit the 300 yard gong. Other than poor marksmanship I dont think that another inc and a half barrel mattered, AR service rifles in competition are going out to 600

Roo
11-06-2007, 12:32 PM
haha thanks for the answers. I'm having a difference
of opinion with some ex marine in my class who says you loose a significant amount of distance and velocity with a 14.5 and anyone that uses one is a more interested in a safe queen than a real gun.... if anyone cares to get me the data off arf that would be nice. I am on my phone and arf isn't a phone friendly site ;p

thmpr
11-06-2007, 12:34 PM
From a 14.5 to a 20 inch barrel, the fps lost is around 150 to 250 fps. From a 16", less than a 75.if you plan to shoot at 600 yards, go with a 20" setup.

Fjold
11-06-2007, 1:10 PM
I found a chart. I don't know how accurate it is but it was on the internet so it must be true. :p

http://img.photobucket.com/albums/v214/Fjold/223graph.jpg

SemiAutoSam
11-06-2007, 1:18 PM
Loose or Lose ?
Is the Barrel loose ?
Did you lose your keys again ?

4 Brigada
11-06-2007, 1:23 PM
Thats a weird chart, cause 0 inches of barrel still produces muzzle velocity of 1800fps, but if its from the internet, who are we to doubt it:shrug:

E Pluribus Unum
11-06-2007, 1:24 PM
So where do I find a 40 inch AR barrel?

The irons would be more accurate too.... :)

Roo
11-06-2007, 2:36 PM
Loose or Lose ?
Is the Barrel loose ?
Did you lose your keys again ?

Is this a gun forum or an English class?

jandmtv
11-06-2007, 2:40 PM
a bit of both me belives. lol

WolfMansDad
11-06-2007, 2:44 PM
Only 10%? I thought the difference was greater than that.

ETA: ARF link http://www.jobrelatedstuff.com/lite/topic.html?b=3&f=118&t=341188

CSACANNONEER
11-06-2007, 3:09 PM
There are still too many other variables that you need to take out of the equation. Type (burn rate) and amount of powder, weight of projectile, diameter of barrel, diameter of projectile, how tightly the bullet is seated and all current weather conditions including altitude.

Fjold
11-06-2007, 3:21 PM
Thats a weird chart, cause 0 inches of barrel still produces muzzle velocity of 1800fps, but if its from the internet, who are we to doubt it:shrug:

You could never have a 0" barrel because the chamber is the first ~1.5 inches. Barrels are measured from the bolt face and include the chamber.

The dots are data points and the curve is extrapolated from that.

There are many 30"-36" barrels on NRA match guns.

4 Brigada
11-06-2007, 3:44 PM
The dots are data points and the curve is extrapolated from that.


Exactly the chart should be cropped then to the barrel lengths and the velocities that provided the data points, extrapolate = assume:no:

ar15barrels
11-06-2007, 3:49 PM
So where do I find a 40 inch AR barrel?


I could make one.
It won't be cheap.

ar15barrels
11-06-2007, 3:53 PM
how much distance would you say you loose having a 14.5 over a 16?

How do you define "losing" distance?
Do you have some set velocity threshold that means something to you?
Are you talking about the absolute maximum distance you can drop bullets onto the ground like the artillery guys?
Are you talking about fragmentation range of M855 or M193?

Each of these tests will have different results.

NRAhighpowershooter
11-06-2007, 3:57 PM
Just for poops and grins.. the longest AR barrel I have seen was a 30" barrel for a SpaceGun

ar15barrels
11-06-2007, 4:03 PM
My quickload plot:

http://ar15barrels.com/tech/223plot.gif

AKman
11-06-2007, 4:13 PM
I found a chart. I don't know how accurate it is but it was on the internet so it must be true. :p

http://img.photobucket.com/albums/v214/Fjold/223graph.jpg

There's some serious extrapolation going on in that graph. So, the longer the barrel (within reason), the more time to reach peak gas expansion and acceleration, and thus velocity?

Wasn't Saddamized Insane building a super gun in Iraq that was on the order of 100 yards long?

The best solution is to buy one of each length barrel.:D

PIRATE14
11-06-2007, 4:30 PM
instead of lets say 16" ? how much distance would you say you loose having a 14.5 over a 16?

Well every one asks this question....but maybe 50-100 FPS but it depends on ammo and barrel types......now distance....wouldn't really matter...

20-16" barrel you lose 100-200 FPS.......I usually just say 25-50 FPS per inch of barrel and that is pretty darn close and easy to remember.........

4 Brigada
11-06-2007, 4:46 PM
AR15Barrel thats a proper chart, the other extrapolate=assume. :willy_nilly:

1911man
11-06-2007, 5:16 PM
Barrel vel. vel. engy. engy.
55gr. 62gr. 55 gr. 62gr.

10" 2739fps. 2627 916 950

14.5 3064 2907 1146 1163


16 3132 2989 1198 1230


20 3259 3095 1297 1318


24 3315 3158 1342 1373



I wish i had 18" data, I heard that 18" is the optimum barrel length.

Fjold
11-06-2007, 6:50 PM
I wish i had 18" data, I heard that 18" is the optimum barrel length.


Optimum for what?

SemiAutoSam
11-06-2007, 6:53 PM
It appears for you its both. :rolleyes::D:eek: LOL

Dont worry bout it.

Is this a gun forum or an English class?

E Pluribus Unum
11-06-2007, 11:44 PM
Barrel vel. vel. engy. engy.
55gr. 62gr. 55 gr. 62gr.

10" 2739fps. 2627 916 950

14.5 3064 2907 1146 1163


16 3132 2989 1198 1230


20 3259 3095 1297 1318


24 3315 3158 1342 1373



I wish i had 18" data, I heard that 18" is the optimum barrel length.


Velocity only equals more energy to the point that it goes THROUGH the target. a 1000 fps bullet transfers no less energy to the target than a 2000 fps bullet when shooting paper targets. This is because at the point that one penetrates through the target, the left over energy keeps going.

J_Rock
11-07-2007, 12:51 AM
As for the question of distance lost you need to look at where the bullet drops below the speed of sound(1128 ft/sec). Once it drops below that point the bullet will destabilize significantly enough to degrade accuracy to the point where you probably wont be able to hit much at that distance.