It sounds like the wing tube is hitting the screw hole. Slide the tube into the wing until it stops. Mark the tube with tape where it exits the wing or just hold the place with your finger. Then lay the tube on the outside of the wing and see if it stops at the screw hole. If this is the case, you may have to work with the wing tube to get it past the screw hole. Or you can take a dowel rod and use it to work the screw area from the inside. Either should work without a major effort. Whatever you do, do not cut the tube shorter. The wing needs the tube at full length for strength.


David