For the first couple of decades, Estes Industries made core-burning black powder motors. The celebrated (and now very rare)
Estes B14-0 motor was the standard first stage booster in such rockets as the Farside-X because it was unsurpassed in getting 3-stagers and large 2-stagers up and off the launch pad. They were a real PITA and dangerous to make, though, which is why they were discontinued by the Damon-era Estes. For a number of years, Estes then produced a B8 motor, which had a pronounced dimple in the propellant face rather than an actual core. The high-thrust 18mm motors were eventually phased out and the big D motors became Estes Industries' heavy load lofter. Because of the safety issues with making them, I doubt that we will ever see cored BP motors again.
To go along with what Bob said, black powder doesn't scale up well to high power sizes. There were some baby HPR motors made with BP for awhile, but they were quite massive compared to AP motors that delivered the same or greater impulse. If you ever get the chance, hold an Estes E9 in one hand and an Aerotech E30 in the other and compare the weights of these two motors. The weight of the propellant in the Estes motor is 36 grams, while the the propellant in the AT motor weighs 19 grams. Yet the Estes E9 has a total impulse of just about 28 N-s., while the much lighter AT E30 has a total impulse of nearly 40 N-s.
With that being said, though, there is great interest in the mid-power (D, E and F) black powder motors that Quest plans to eventually release.
Mark K.