Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:
what is the average shot volume (cm 3) when the shot diameter (cm) is less than 6.04?

### Inputs:
table_name: table, columns: ['gun class (pdr.)', 'shot diameter (cm)', 'shot volume (cm 3 )', 'approx. service bore (cm)', 'mass of projectile (kg)']

### Response:
SELECT AVG shot volume (cm 3 ) FROM table WHERE shot diameter (cm) < 6.04