75/15/10 is the ratio for standard BP used for lift powder and burst charge. Most rocket fuels are not quite as "hot" of mix. If you have really good charcoal and other quality chemicals in the mix it will be too "hot" of a ratio for BP motors. You could add more charcoal to your BP mix to slow the powder down for a rocket fuel.
Or just keep your good BP for lift and burst charge and make a new batch of BP for rocket fuel.
Most people have a hard time making hot BP, you did a good job save it for what it is best used for.
The only other option is to press your fuel grain at higher pressures to reduce the likely-hood of catos.
Estes presses motors at fairly high pressures on the fuel grain and use strong walled tubes.
Edited by mikeee, 08 August 2015 - 07:38 PM.