Where to get a very fine powder?

[ymg200]

I am not doing reloading and I don't shoot black powder guns, so I don't have much experience with powders.
I need a very fine powder to make model rocket igniters. I am following instructions in this page:
http://www.jacobsrocketry.com/aer/homemade_wire-wound_igniters.htm#Pyrogen
These instructions say that commercial powder is crushed easily by mortar and pestle, but I can't crush the powder that I got from ammo cartridges that I had. I got different grain shapes - cylindrical grain from a rifle cartridge and round flakes from a shot shell and from a pistol round. However, I wasn't able to crush any of these. Cylindrical grain gets squashed into flat, but it doesn't crush. Same result with round flakes.
I need a really fine powder to suspend it in the lacquer as per instructions above.
Making my own powder is not an option because I need a really small amount for igniters, so I want to find a commercial powder that can be crushed.
Thanks all for help.

 

[ArchAngelCD]

DO NOT use the powder you got from ammo, it is not the correct powder. You need to use Black Powder not smokeless powder. You need to buy FFFFg powder made by any one of several companies, GOEX being the most popular recently.

Shipping might be a problem, more and more stores are not shipping BP because it's explosive. If you have a Bass Pro Shop near you, you can probably buy it there.

 

[ymg200]

ArchAngelCD, thank you. I did not realize that smokeless powder is that much different from black powder. The link that I referenced also shows the can of 4F Goex powder, just like you said.