Most people put to much powder and a lot of them put it in the wrong place, puting the powder away from the flash hole works best if you cover up the flash hole it has to burn through it to set the load off this takes longer.
My method is to start at the outside edge of the flash pan and taper it down as it goes toward the touch hole stoping a little short.
I use flowered blasting powder its about 6F and it has no graphite in it so the spark does not have to burn through the graphite to flash the prime. This is what works for me. Lee