The projectile was created similar to the one in the picture: https://safebooru.org/index.php?page=post&s=view&id=2591792
I like Akiyama Yukari

The model consists of 5 parts and 4 rods
After printing, you can simply insert them or glue them for stability if you want to carry it. The overall length of the projectile is 960 mm, the width of the bottom is 105 mm
For convenience, I have attached a blender file so that you can cut everything for yourself and for the dimensions of your printer. The projectile can be printed separately if you do not need a casing. The model, of course, is not the most detailed, since I have no experience in blending (I could not curl the tip of the projectile, so it will have to be processed with sandpaper to round it off

Projectile dimensions: x, y = 88mm, z = 400mm
Sleeve: x, y = 105mm, z = 571mm