Michael Courtney
Silver Member
We've developed a method to accurately determine the average frictional force between the bullet and the rifle bore that is accurate within 1-2% and requires about 20 test shots to determine the friction of a particular bullet/coating/bore combination.
Naturally, our next inclination is to quantify the barrel friction resulting from different bullet coatings: HBN, Moly, and WS2. We are leaning toward testing each coating in each of two bullet designs, a conventional jacketed lead bullet and a solid copper bullet in our .223 test rifle. Of course, the rifle barrel will need to be thoroughly cleaned when moving between coatings and before beginning.
A few questions, if you are willing to lend your advice to our experimental design:
1. Should we also test lubalox, the Combined Technology coating? This would constrain our design to one of the .224" bullets available from the factory with this coating. We would also obtain the equivalent uncoated Nosler ballistic tip and get them coated with the other three coatings. Frankly, we'd prefer not to test lubalox, because it locks us into the ballistic tip, and we'd rather test a match bullet from Sierra, Berger, or Hornady. On the other hand, we do think Nosler might be exaggerating the friction reducing claims of lubalox and it would be nice to debunk test the claim.
2. In order to enhance uniformity (because we have so little bullet coating experience), we plan to send the bullets to NECO for moly coating and SSS for HBN. Is there a commercial service that offers WS2 coating, or do we need to roll our own here? Perhaps you can suggest someone with experience coating bullets with WS2 who might be willing to coat a couple of boxes for us. Is WS2 even still used as a common bullet coating? Is it a waste of time to test it, or is there interest?
3. Our .223 Rem test barrel has a 1 in 12" twist which limits us to bullet weights up to 69 grains at our test facility. (We can shoot heavier bullets because of the thin air up here.) Is there a particular match bullet you'd recommend. A bullet with the most uniform bearing surface would be optimal, because preliminary testing (uncoated bullets) suggests that bearing surface has an impact on friction, and it would be optimal to minimize confounding factors so we can emphasize the effects of the coating.
Of course, any other insight or advice you can offer would be greatly appreciated.
Naturally, our next inclination is to quantify the barrel friction resulting from different bullet coatings: HBN, Moly, and WS2. We are leaning toward testing each coating in each of two bullet designs, a conventional jacketed lead bullet and a solid copper bullet in our .223 test rifle. Of course, the rifle barrel will need to be thoroughly cleaned when moving between coatings and before beginning.
A few questions, if you are willing to lend your advice to our experimental design:
1. Should we also test lubalox, the Combined Technology coating? This would constrain our design to one of the .224" bullets available from the factory with this coating. We would also obtain the equivalent uncoated Nosler ballistic tip and get them coated with the other three coatings. Frankly, we'd prefer not to test lubalox, because it locks us into the ballistic tip, and we'd rather test a match bullet from Sierra, Berger, or Hornady. On the other hand, we do think Nosler might be exaggerating the friction reducing claims of lubalox and it would be nice to debunk test the claim.
2. In order to enhance uniformity (because we have so little bullet coating experience), we plan to send the bullets to NECO for moly coating and SSS for HBN. Is there a commercial service that offers WS2 coating, or do we need to roll our own here? Perhaps you can suggest someone with experience coating bullets with WS2 who might be willing to coat a couple of boxes for us. Is WS2 even still used as a common bullet coating? Is it a waste of time to test it, or is there interest?
3. Our .223 Rem test barrel has a 1 in 12" twist which limits us to bullet weights up to 69 grains at our test facility. (We can shoot heavier bullets because of the thin air up here.) Is there a particular match bullet you'd recommend. A bullet with the most uniform bearing surface would be optimal, because preliminary testing (uncoated bullets) suggests that bearing surface has an impact on friction, and it would be optimal to minimize confounding factors so we can emphasize the effects of the coating.
Of course, any other insight or advice you can offer would be greatly appreciated.