We poured our first 12 x 20" (300 x 500mm) grain for our suborbital booster motor last Saturday at FAR and will be casting more next month for a static test. We will also be static testing our 6" (150mm) second stage motor next month. For the booster motor, each grain has a mass of 130 pounds (~55 km) of propellant.
https://www.flickr.com/photos/48721294@ ... ed-friend/
Rick