VERY interesting read:
The Truth About Barrel Length, Muzzle Velocity and Accuracy | The Truth About Guns
The Truth About Barrel Length, Muzzle Velocity and Accuracy | The Truth About Guns
Range Report Barrel length vs muzzle velocity vs accuracy test
- Thread starter TiroFijo
- Start date
Good read. My biggest question about this article, however stems fro the following quote:
Overall, as demonstrated in the accuracy charts, the shortest barrel length provided the most consistent accuracy across the board and the longest length proved to be the least accurate with the same loads.
A lot of time has been devoted on this forum to discussions about OCW and OBT. The conclusions drawn in the quote article relate to the same ammo being used in all the barrel lengths. It seems to me that a major component of accuracy/velocity and how the relate to barrel length has been over-looked.
I should be very interested in any input from Dan Newbury or possibly one of our "resident" ballisticians---Kevin Thomas or Bryan Litz???
Cheers,
Tim
The Right to Keep and Bear Arms Shall NOT be Infringed
Overall, as demonstrated in the accuracy charts, the shortest barrel length provided the most consistent accuracy across the board and the longest length proved to be the least accurate with the same loads.
A lot of time has been devoted on this forum to discussions about OCW and OBT. The conclusions drawn in the quote article relate to the same ammo being used in all the barrel lengths. It seems to me that a major component of accuracy/velocity and how the relate to barrel length has been over-looked.
I should be very interested in any input from Dan Newbury or possibly one of our "resident" ballisticians---Kevin Thomas or Bryan Litz???
Cheers,
Tim
The Right to Keep and Bear Arms Shall NOT be Infringed
Simple concept really... Accuracy doesn't come from velocity. It comes from repeatability and a shorter barrel is more rigid allowing for more consistency.
Sent from my SGH-T769 using Tapatalk 2
Sent from my SGH-T769 using Tapatalk 2
But, if you can get the right harmonics for you load versus the longer barrel, then you have the repeat ability back. This study fails to address customizing the load for the rifle. That is what OCW or OBT does. Therefore, their results are not totally sound from a scientific basis.
Cheers,
Tim
The Right to Keep and Bear Arms Shall NOT be Infringed
Cheers,
Tim
The Right to Keep and Bear Arms Shall NOT be Infringed
I doubt someone would have the means and time for a truly "scientific" test... this is a sample of one, but very well done. Perhaps a different barrel (even from the same maker) would probably give slightly different results, both in accuracy and velocity. Add many more factory and custom loads, firing many 10 shot groups to truly validate the results, etc. and the potential combinations would wear the barrel before the end of the test.
Shorter barrel = more rigid (exponentially!) this is just ONE element regarding accuracy, but an important one.
We all know someone could tailor the loads to the rifle, but the rifle (with free floating) more rigid barrel would have the advantage across a wide variety of loads, at least at closer ranges. At long range practical accuracy is very influenced by wind drift and (given same bullet BC) muzzle velocity.
I would like to see what are the powders ideally suited for max velocity in shorter barrels. It seems the heavy bullets have a little less velociyt loss per inch, but the very small velocity loss for the 175 SMK federal match load (only 15.6 fps/inch) seems almost incredible.
The 7.62N Mk319 SOST load have impressive velocities out of short barrels (16" and 13"), I wonder what powder is used.
Shorter barrel = more rigid (exponentially!) this is just ONE element regarding accuracy, but an important one.
We all know someone could tailor the loads to the rifle, but the rifle (with free floating) more rigid barrel would have the advantage across a wide variety of loads, at least at closer ranges. At long range practical accuracy is very influenced by wind drift and (given same bullet BC) muzzle velocity.
I would like to see what are the powders ideally suited for max velocity in shorter barrels. It seems the heavy bullets have a little less velociyt loss per inch, but the very small velocity loss for the 175 SMK federal match load (only 15.6 fps/inch) seems almost incredible.
The 7.62N Mk319 SOST load have impressive velocities out of short barrels (16" and 13"), I wonder what powder is used.
The article comes off as if to say that is the end of the story. There is more to it. I suppose if your shooting 18" steel like they were even at 100 yards is makes zero difference. Hell off the shelf Remington hunting rifles can do that.
This test was a VERY in-precise test. All I see is say is that "any" gun can hit IPSC steel, yep well an 12x24 steel target is REALLY easy to hit guys. The article comes off as if to say that is the end of the story. As much as they try and dispels internet know it all's and trolls which they go out of their way to mention, I fear they just become one stating they have the answer, by all accounts that test showed no difference in barrel length when hitting a big ass target. Well ya, we all knew that.
So yes, they showed a 20" barrel will do just as good as a 26" barrel shooting zombies during a Zombie invasion. Frankly Tiger woods can do that with a golf ball and a club too.
They did mention that they were shooting BIG ASS TARGETS btw, but I am sure people will miss that part. This test is so broad in terms of what they mean by accuracy, they need to try shooting that .308 at a 5" circle at 1000 yards and see if it makes a difference.
Interesting. Wrong conclusion, but interesting.
This sentence is what undoes the whole thing:
"Increased drift is not the end of the world, though, and if measured properly, can be overcome with ease."
This sentence is what undoes the whole thing:
"Increased drift is not the end of the world, though, and if measured properly, can be overcome with ease."
Perhaps you missed this part:
"Group size was measured with a micrometer. Five shot groups were used to measure accuracy. Firing was conducted on standard IPSC silhouette targets at all ranges."
It doesn't matter the size of the target, it is the size of the groups that matters. And if you plan to shoot a 5" target at 1000 yds the the 308 is not the ideal caliber to start with...
Whatever else, data is always interesting. Thank you for the post.
Most everyone here knows that each bullet and barrel must have a separate powder adjustment to get max. velocity consistent with harmonic control. At theoretical optimum, the energy of the bullet, .5 m v^2 will go up proportional to length, that is, limited by the internal pressure doing work on a bullet over longer distance. Some of this may be lost to harmonic control.
And I am pretty sure that bending moment for a cantilever is the fourth power of the length, not the often maligned "exponential".
The wiki entry on "bending" has some interesting figures. Bending - Wikipedia, the free encyclopedia But even a fourth power function is
very hard to keep control of and could require a massive barrel to keep from whipping.
Most everyone here knows that each bullet and barrel must have a separate powder adjustment to get max. velocity consistent with harmonic control. At theoretical optimum, the energy of the bullet, .5 m v^2 will go up proportional to length, that is, limited by the internal pressure doing work on a bullet over longer distance. Some of this may be lost to harmonic control.
And I am pretty sure that bending moment for a cantilever is the fourth power of the length, not the often maligned "exponential".
The wiki entry on "bending" has some interesting figures. Bending - Wikipedia, the free encyclopedia But even a fourth power function is
very hard to keep control of and could require a massive barrel to keep from whipping.
EDIT: Hahahha, that's exactly what I copied in pasted ... they used the word "ease".
"Increased drift is not the end of the world, though, and if measured properly, can be overcome with ease."
Wind error is pretty much proportional to muzzle velocity loss; so unless you are proportionally gaining precision - you are "net" losing accuracy.
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Sort of like saying "Not having the technology to fly a man to Mars isn't the end of the world, though, and if developed properly, can be overcome with ease."
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