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Testing Friction Reduction of Bullet Coatings

 
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Old 07-28-2012, 08:48 PM
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Testing Friction Reduction of Bullet Coatings

The Aug 2012 issue of Precision Shooting contains an article comparing the friction reducing effects of MS2, WS2, HBN, and Lubalox. The research was performed with cadets at the Air Force Academy who co-authored the article. The title is "Friction Effects of Common Bullet Coatings in 5.56mm NATO" and uses the same technique as the earlier article originally published in the March 2012 issue of Precision Shooting and reprinted here. The results were somewhat surprising to us.
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Old 08-06-2012, 07:39 PM
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Re: Testing Friction Reduction of Bullet Coatings

Anybody read the article? Any questions or comments?
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Old 08-07-2012, 08:57 AM
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Re: Testing Friction Reduction of Bullet Coatings

I don't suppose the is a link to a website we can use is there?

I'm seriously considering HBN on one or two of my rigs....
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Old 08-07-2012, 06:36 PM
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Re: Testing Friction Reduction of Bullet Coatings

Quote:
Originally Posted by Outlaw6.0 View Post
I don't suppose the is a link to a website we can use is there?

I'm seriously considering HBN on one or two of my rigs....
In the 5.56mm test barrel, HBN reduced the friction on the 55 NBT by 15%, the 62 BFB by 12%, and the 55 TTSX by < 1%. The report is not available on the web that I know of. The earlier report describing the method was posted here:

Measuring Barrel Friction In The 5.56mm NATO

To me, these modest friction reductions do not warrant the time, effort, and expense of coating with HBN.
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Old 08-08-2012, 09:09 AM
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Re: Testing Friction Reduction of Bullet Coatings

Quote:
Originally Posted by Michael Courtney View Post
In the 5.56mm test barrel, HBN reduced the friction on the 55 NBT by 15%, the 62 BFB by 12%, and the 55 TTSX by < 1%. The report is not available on the web that I know of. The earlier report describing the method was posted here:

Measuring Barrel Friction In The 5.56mm NATO

To me, these modest friction reductions do not warrant the time, effort, and expense of coating with HBN.


I wouldn't mind seeing the same test conducted on a bullet with a long bearing surface, say a 7mm-180grn Berger or a 338- 300grn SMK. It makes me think (I hate it when that happens!) that as bearing surface goes up, friction reduction would also go up...? Who knows....


As far as price, effort etc goes, Copper Creek will HBN up to 1k projectiles for $30.00 & that includes return shipping. At less than .03/round, I am going to give'er a try

http://coppercreekammo.com/index.php...products_id=94


t
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Old 08-08-2012, 09:31 AM
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Re: Testing Friction Reduction of Bullet Coatings

Quote:
Originally Posted by Outlaw6.0 View Post
I wouldn't mind seeing the same test conducted on a bullet with a long bearing surface, say a 7mm-180grn Berger or a 338- 300grn SMK. It makes me think (I hate it when that happens!) that as bearing surface goes up, friction reduction would also go up...? Who knows....


As far as price, effort etc goes, Copper Creek will HBN up to 1k projectiles for $30.00 & that includes return shipping. At less than .03/round, I am going to give'er a try

Boron Nitride Coating Boron Nitride Bullet Coating [] - $29.99 : Copper Creek Cartridge Co.


t
You have some good insights. As bearing surface increases, friction usually increases also for the bullets we've tested. However, bullet construction is a bigger factor, and a solid copper bullet or a bullet with a steel core will usually have much more friction than a similar length jacketed lead bullet.

However, I would not think a lubricant would reduce friction by more than about the same percentage in a bullet with a longer bearing surface. It might be 12% of a bigger uncoated friction, therefore a bigger gain, but the percentage gain would be unlikely to be more than 12-15%. We've tested a lot of bullets with a lot of coatings and 15% is the best friction reduction we've ever seen.

For example, the 55 NBT lost 245 ft-lbs of energy to friction uncoated, and the 62 BFB (longer bearing surface) lost 330 ft-lbs of energy to friction uncoated. The coating of HBN reduced the friction by 15% and 12%, respectively. After these mediocre results, I've stopped coating my 140 AMAX (very long bearing surface) bullets in 6.5x284 and I've seen no negative results.

In fact, the testing we've done also shows that uncoated bullets have smaller shot-to-shot velocity variations. Not that coated bullets can't have impressive extreme spreads and standard deviations in velocity. In some cases they can. But in the bullet's we've tested, extreme spreads and standard deviations of uncoated bullets are consistently smaller.
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Old 08-08-2012, 10:22 AM
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Re: Testing Friction Reduction of Bullet Coatings

Interesting topic for sure. In your 6.5x284 with 140 A-Max setup, what was the velocity difference utilizing the same load running coated vs uncoated?

There is a TON of information regarding the effects of lubricant on the bullet; how about the effects on the bore? Less friction should, & I say should, promote longevity of the bore life; should it not? 2nd, running a coated bullet, shouldn't copper fouling be reduced to a near zero amount?


t
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