To dream of hearing a gunshot represents your awareness of someone else in your life making a powerful decision or warning. It may also reflect your awareness of the delayed consequences of a decision you made finally making itself present in your life.
Alternatively, gunshots may reflect dangerous or powerful choices. Choices with consequences.
Example: A woman dreamed that her two family dogs were shot to death. In waking she had experienced a a premature labor and delivery and lost her twin sons. The deaths may have reflected her feelings about how unexpectedly powerful and dangerous she felt that some of her life choices were that resulted in the premature labor.