My kids have had orders for a couple of years now, to mix me with a couple of 8 lb jugs of W231, load me into as many .45acp as they can, then run them through my 1911 until they are gone. Already have the brass, lead for the bullets, and enough cash for the powder and primers stashed away.
I read, at least 15 years ago, where you could be cremated, loaded into a shotshell, and shot at the wild game of your choice. I think that would be neat, to be loaded in the wadding of a 12ga slug, and someone to shoot me at that trophy buck. Every time they went to that specific place, or went out deer hunting, or even saw that monster's rack on the wall, it would be in memory of me!
The only concern I would have about mixing my ashes with the gunpowder, would be making sure that the weight and volume of the ashes did not dilute the powder charge. I guess if you mixed it with 16lbs of powder, it would not dilute it very badly. Your kids would surely be shooting A LOT of .45you!!