[1] Impacts on the parent body of a meteoroid can produce very large pressures.
Meteorites are often given a rating from 1 to 6 showing the level of shock metamorphism.
However, the degree of shock can vary within a meteorite on the scale of centimeters.
[2] Smaller bodies colliding with one another would not have sufficiently great impact velocity to produce the pressures and temperatures required to produce shock effects, due to their lesser gravitational attraction for one another.
Many of the shocked veins formed at the boundaries of polished surfaces of brecciated specimens exhibit intricate spider-web-like structures.