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
Testing Friction Reduction of Bullet Coatings
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="Michael Courtney" data-source="post: 683120" data-attributes="member: 28191"><p>None of the lubricants tested reduced the friction in the Barnes bullet more than 1%, and MS2 and WS2 actually increased the friction. With the 55 NBT, HBN decreased the friction by 15%, while WS2, MS2, and Lubalox all increased the friction. For the 62 BFB, the coatings decreased the friction by 7% to 15%.</p><p></p><p>Based on these observations, an educated guess might be that bullets with thinner jackets and softer cores might tend to get more friction reductions by coating.</p><p></p><p>I'll leave it as an open question why the Barnes bullet got so little benefit. One hypothesis is that it is the smaller bearing surface due to the grooves. Another hypothesis is that it is due to the hardness of the copper and larger normal forces between the bullet and barrel.</p><p></p><p>We have repeatedly observed that steel core bullets and solid copper bullets tend to have much larger friction (uncoated) than jacketed lead bullets, and jacketed lead bullets with thin jackets and soft lead cores tend to have less friction than "stouter" bullets with thicker jackets and harder lead cores. </p><p></p><p>It has also been reported to us by other parties in private communication that attempts to use coatings to reduce the friction of (ungrooved) solid copper bullets have been unsuccessful. This is consistent with the observation that Barnes itself was once coating their bullets but has since stopped marketing coated bullets.</p><p></p><p>I've also seen data (not as careful a study as our published friction work) that suggests that solid brass bullets (uncoated with grooves) have friction closer to solid copper bullets (uncoated with grooves) than to thin jacketed soft core match type bullets.</p><p></p><p>Don't get me wrong. I'm a big fan of solid copper bullets, and especially the Barnes TTSX design and I'd recommend them highly for a number of applications. My family's elk loads in both 25-06 and 30-06 use Barnes TTSX bullets. But the increased friction is a trade-off of using solid copper bullets, and we are careful to use data developed specifically for solid copper bullets and carefully watch for pressure signs when working up loads. In .308 Win, I have been unable to work up a suitable load for solid copper bullets that was fast enough for the range capabilities I desired.</p></blockquote><p></p>
[QUOTE="Michael Courtney, post: 683120, member: 28191"] None of the lubricants tested reduced the friction in the Barnes bullet more than 1%, and MS2 and WS2 actually increased the friction. With the 55 NBT, HBN decreased the friction by 15%, while WS2, MS2, and Lubalox all increased the friction. For the 62 BFB, the coatings decreased the friction by 7% to 15%. Based on these observations, an educated guess might be that bullets with thinner jackets and softer cores might tend to get more friction reductions by coating. I'll leave it as an open question why the Barnes bullet got so little benefit. One hypothesis is that it is the smaller bearing surface due to the grooves. Another hypothesis is that it is due to the hardness of the copper and larger normal forces between the bullet and barrel. We have repeatedly observed that steel core bullets and solid copper bullets tend to have much larger friction (uncoated) than jacketed lead bullets, and jacketed lead bullets with thin jackets and soft lead cores tend to have less friction than "stouter" bullets with thicker jackets and harder lead cores. It has also been reported to us by other parties in private communication that attempts to use coatings to reduce the friction of (ungrooved) solid copper bullets have been unsuccessful. This is consistent with the observation that Barnes itself was once coating their bullets but has since stopped marketing coated bullets. I've also seen data (not as careful a study as our published friction work) that suggests that solid brass bullets (uncoated with grooves) have friction closer to solid copper bullets (uncoated with grooves) than to thin jacketed soft core match type bullets. Don't get me wrong. I'm a big fan of solid copper bullets, and especially the Barnes TTSX design and I'd recommend them highly for a number of applications. My family's elk loads in both 25-06 and 30-06 use Barnes TTSX bullets. But the increased friction is a trade-off of using solid copper bullets, and we are careful to use data developed specifically for solid copper bullets and carefully watch for pressure signs when working up loads. In .308 Win, I have been unable to work up a suitable load for solid copper bullets that was fast enough for the range capabilities I desired. [/QUOTE]
Insert quotes…
Verification
Post reply
Forums
Rifles, Reloading, Optics, Equipment
Rifles, Bullets, Barrels & Ballistics
Testing Friction Reduction of Bullet Coatings
Top