Tubelock used a copper tube filled with fulminate. Stuck it into the touch-hole, lock made with a hammer to crush it. Great ignition, I think popular with the British for waterfowling before the cap came into vogue.
See p58-59, p90-100 of Early Percussion Firearms, Lewis Winant 1959.
I do not think it would be very much fun to make one's own fulminate tubes.