Definition of "obturating" []

• That stops or plugs up; used in closing or stopping up: specifically applied to a primer for exploding the charge of powder in a cannon, and at the same time closing the vent, thus preventing the rush of gas through it in firing.

The Century Dictionary (Public Domain)

• "Then, to stop this "erosion," the obturating (sealing) primer came into use."
• "When you called a "mortar bomb rubber ring" an "obturating ring" ..."