Back then, Campy made Record and Nuovo Record BB sets. The difference was NR had thicker cups with a spiral groove cut in the cup, in the hole where the spindle passes through the cup. Supposed to expel water/dirt, dunno if it worked... But the main upshot is, spindles made for thick NR cups have their two cones closer together.

Sounds like maybe your spindle is too narrow, in the spacing between the cones, i.e. you might be using an NR spindle with a Record (thin wall) cup.

Does your cup have a spiral groove in the spindle hole?