Forums
New posts
Search forums
What's new
Articles
Latest reviews
Author list
Classifieds
Log in
Register
What's new
Search
Search
Search titles and first posts only
Search titles only
By:
New posts
Search forums
Menu
Log in
Register
Install the app
Install
Forums
Rifles, Reloading, Optics, Equipment
Rifles, Bullets, Barrels & Ballistics
Mitigating Barrel Whip and Harmonics
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Reply to thread
Message
<blockquote data-quote="kduffy" data-source="post: 1766563" data-attributes="member: 76083"><p>Find the area of the barrel exterior. Find the area of a flute, (you need to know the diameter of the ball endmill used). Subtract the width of the flute area (remember you can only measure the chord length) from the barrel exterior area. Add the new area created by the radius of the endmill, at depth of flute, plus the area of any flute deeper than the radius of the endmill. When you are done, your new area is some percentage greater than the orginal area. This is a rough outline, you will need to pull out a geometry book to find all the arc lengths and really get accurate with the calculation. </p><p></p><p>It may be best and easiest to use a computer drafting program to "make" a barrel and then let the computer calculate the areas. </p><p></p><p>There may be some benefits of a shorter distance to the bore and "broken" surface to allow for more heat transfer. My recollection is that tube wall thickness makes more difference than surface area in heat transfer, but it has been a few years since I studied that. I believe these may total more than the minimal increase in surface area. When you work through all the math, the the percentages of gain I expect to be in the single digits.</p><p></p><p>My impression is that with fluting, you simply get the rigidity benefits of a larger barrel diameter due to the greater moment of inertia (squared factor)(just like an I beam gets much stiffer as it gets taller), with the benefit of the lighter weight of a slimmer profile. There may be some benefit to reduced mass, (and the spiral fluting could make the rotational acceleration of the bullet offset some of the energy). All of these will have effects on the harmonics just like tuning a stringed instrument. A change of 15% or more from a harmonic is best, but you take what you can get.</p><p></p><p>The bullet simply does not outrun the speed of the vibration in the steel. This leads us back to simply timing the bullet exit to the barrel harmonics with consistency at the most favorable node.</p></blockquote><p></p>
[QUOTE="kduffy, post: 1766563, member: 76083"] Find the area of the barrel exterior. Find the area of a flute, (you need to know the diameter of the ball endmill used). Subtract the width of the flute area (remember you can only measure the chord length) from the barrel exterior area. Add the new area created by the radius of the endmill, at depth of flute, plus the area of any flute deeper than the radius of the endmill. When you are done, your new area is some percentage greater than the orginal area. This is a rough outline, you will need to pull out a geometry book to find all the arc lengths and really get accurate with the calculation. It may be best and easiest to use a computer drafting program to "make" a barrel and then let the computer calculate the areas. There may be some benefits of a shorter distance to the bore and "broken" surface to allow for more heat transfer. My recollection is that tube wall thickness makes more difference than surface area in heat transfer, but it has been a few years since I studied that. I believe these may total more than the minimal increase in surface area. When you work through all the math, the the percentages of gain I expect to be in the single digits. My impression is that with fluting, you simply get the rigidity benefits of a larger barrel diameter due to the greater moment of inertia (squared factor)(just like an I beam gets much stiffer as it gets taller), with the benefit of the lighter weight of a slimmer profile. There may be some benefit to reduced mass, (and the spiral fluting could make the rotational acceleration of the bullet offset some of the energy). All of these will have effects on the harmonics just like tuning a stringed instrument. A change of 15% or more from a harmonic is best, but you take what you can get. The bullet simply does not outrun the speed of the vibration in the steel. This leads us back to simply timing the bullet exit to the barrel harmonics with consistency at the most favorable node. [/QUOTE]
Insert quotes…
Verification
Post reply
Forums
Rifles, Reloading, Optics, Equipment
Rifles, Bullets, Barrels & Ballistics
Mitigating Barrel Whip and Harmonics
Top