I've launched my Estes Phoenix twice and my Airspike (Mustang) once on some old Aerotech E18W reloads. How old? Not exacly sure, but the delays were
10 seconds unmodified, and those are not in production anymore.Anyway, what I have found is that if you sand the slot out with 80 grit and use a replacement copperhead made for the big motors it lights. The first two I tried the stock ignitors and even some cute little two lead ignitors. Neither fired until I used the replacement Copperhead.
The igniters that come with the 24mm reloads are short and have relatively little pyrogen. They do not make solid contact with the grain in the slot. The 8" replacement copperheads are thick and need to be stuffed into the slot from the side, even after sanding. Leave as much of the sanded off dust in the slot as you can to act as ignitor pyrogen as well.