3.125" O.D. and almost 3.0"I.D. Nosecone one that I made in Fusion and printed in PETG a while ago and it did not fit for that project (8hr print). The wrap is a test of my printing and scaling abilities, it is a little short and needs to be scaled a hair more. 24mm mount, so I can use what I have. The goal as usual make something from almost anything I have around or given to me. I did buy some 1/8" Birch ply today from HL. I want a cool launch and height of around 400' and from OR that is very possible and then some with my current reloads and stock of BP.