The entire mass of smokeless powder is not dependent upon the detonator's impulse, only the smokeless powder that was in close proximity to the detonator.
As Bullseye powder contains around 40% Nitroglycerine, I would expect once the powder was detonating, that additional powder would also detonate even if separated from the initial quantity some small distance away.
Similar to ditch blasting where the impulse from one charge propagates through the ground to the next charge, separated by a couple feet of earth.