Since a 29mm motor, or 24mm E motor can fit in a BT-56, why not a Booster 56, Estes, slightly larger than the Booster 55, yet smaller than the 2 inch PSII Booster 9752? The BT-56 body tubes are really thick, heavy duty tubes, for the Estes Challenger II, easily PSII worthy tubes and standard thickness for the Estes AstroCam110 standard fin can. I'd like to see how high the old AstroCam110 will go and NC-56 also makes a great Boat-tail to 18mm motors;-)

Nice nose cone replacements, for the old Estes Challenger II, 24mm motor powered booster, of the discontinued Estes Astro Cam110, just wish Estes would have the BT-56 body tubes available. Hint, hint Estes, there's a matching one piece fin also, just like the Booster 55.