obturating cup

obturating cup

[′äb·tə‚rād·iŋ ‚kəp]
(ordnance)
An inverted cup, sealing against passage of gases of explosion, which inverts due to pressure and actuates a firing pin or other mechanism.
References in periodicals archive ?
According to Greg Palkowitsh, who engineered the bullet, the FPB has an obturating cup, otherwise known as a hollow base.