An irregular separation or rupture through the paper or package. Air Shear burst: Burst caused by air trapped in the winding roll producing rupture of the web along the machine direction. Caliper shear burst. Cross Machine tension burst that generally occurs between an area or relatively high and low caliper extending for some distance in the machine direction; due to non uniform nip velocities between hard and soft sections of the roll. Core burst: Inter-layer slippage just above the core, often over the key way, which terminates an Air Shear Burst. Core bursts are most often seen on core-supported unwinds and winders.