Semroc Maxi Micron had a very nice flight on a B6-4 motor. I flew it again on a C6-3 motor and it too was a beautiful, straight boost. I really like how this rocket flies. It is perfect for smaller fields like the Big Bertha. The Semroc Maxi Micron is a 250 % upscale of the original Centuri Micron from back in the early 60's