Final answer:
The M557 is a mechanical time fuze for artillery shells with settings for delay and quick action, which are adjusted pre-firing for tactical outcomes.
Step-by-step explanation:
The M557 is a type of mechanical time fuze used in artillery shells. It’s designed to be set to detonate the shell at a specific time after being fired. The M557 allows for various settings, including delay action and quick action, depending on the tactical need. In the delay action setting, the fuze is programmed to detonate after the shell has penetrated a target, while in the quick action setting, the fuze detonates upon impact or at a predetermined time in the air. These settings can be adjusted before firing to ensure the shell's explosion aligns with the desired tactical outcome.