Yet another useless repressive law. Oh, well.
You could get up a group buy and split up a pound of FFFFg.
An ounce will prime a lot of pans. You could stagger your buys of FFFg and level out cans of that at <15 oz.
You could prime with FFFg, the Army primed out of their cartridges of Musket grain.
You could grind A LITTLE powder finer with a non-sparking mortar and pestle or just a couple of spoons.
Geez, I have an annual four day BPCR shoot in Georgia. I shoot up about a pound and a half over a long weekend. Not allowed in California, by that law.