Making Rocket Body (2): Cone does not fit into the PVC pipe smoothly

As evident on the photo, the cone cannot fit into the pipe because its minimum diameter (the part where it must smoothly fit with the inner wall of the pipe) is too large (or too exact). After I print the wings of the rocket (design procedure video in my CAD design website: https://sites.google.com/pupils.nlcsjeju.kr/moojokim-3d-cad-modeling/23-rocket-parts), I am going to print another cone with a decreased minimum diameter and I hope that will fit in well with the inner wall of the PVC pipe.