bourrelet

noun3

1. •
   An accurately machined portion around the diameter of a shell of a gun, which acts to increase accuracy of projectile fit to the barrel.

   • The bourrelet is a slightly raised surface on the rocket designed to maintain a light contact with the inside of the launching tube to center the rocket when fired. — 2019
2. •
   A raised rim around a footprint consisting of sediment displaced by the pressure of the step.
3. •
   An escoffion.