Fancy bullet coatings

[ochadd]

Anyone here used hBN and WS2? Experiences with it?

Read an article @ http://www.6mmbr.com/bulletcoating.html

Found someone selling enough to do around 8000 bullets for $20 of the hBN. More than enough to give it a go and see what happens. Only goal would be to speed up the cleaning process and maybe have some unique looking bullets. 8000 rounds is a solid 2-3 years of ammo for me so the price isn't a concern.

Supposedly all the so called improvements of moly with none of the down sides.

 

[Lee Roder]

Interesting

Just reading the article I stumbled over the fact that

"Anti-friction coatings are Speed Robbers. You can expect to lose 20-80 fps after coating your bullets, maybe more with large cartridges and bullets with long bearing surfaces."

Isn't it increased friction and not decreased friction which reduces bullet velocity? I thought this was the reason that cast bullets normally give slightly higher velocity than jacketed at the same pressures.

Pressures can obviously decrease with decreased friction but I'd think that such decrease would be a consequence of faster bullet velocity and not a cause of reduced bullet velocity. If the bullet travels faster down the barrel outrunning expanding gases, charges being equal, pressure will be lower.

Apparently my view of reality here is wrong. I feel like a physics retard. What am I missing?

 

[Walkalong]

With slick Moly bullets, pressures go down with the same charge, so velocities go down.

To get the same velocity with Moly bullets you must increase the powder a bit.

That was one of the selling points of Moly in the beginning, the ability to get better velocities .

 

[ochadd]

I've read somewhere that the pressures and friction don't change equally with coated vs normal bullets. My understanding of it means that with an uncoated bullet you may get
3400 fps with 25 grains of powder at max. The same powder charge would get you 3350 fps with a coated bullet. You could then run the charge up to 26 grains and make 3500 with a coated bullet and still have the same pressure as 25 grains for 3400 fps.