Until the baseplate is firmly seated, what must you do with the M67 sight prior to firing?

Prior to firing the mortar with the baseplate not yet firmly seated, it is crucial to remove the M67 sight from the mortar. This is essential to ensure safety and maintain accuracy, as an unsteady or improperly placed baseplate can lead to misalignment and potential malfunction during operation. The sight must be securely attached only after the baseplate is seated properly, ensuring that it will provide accurate targeting. In this context, keeping the sight removed until the baseplate is secure helps prevent any accidental damage or inaccurate adjustments that could occur due to a lack of stability.