Leads is a generic word in this case. What you're really asking me is when does the contact report fall in the reaction to enemy fire/sighting.
At an enemy sighting where the squad hasn't come under fire the contact report is sent as soon as possible.
If the squad is engaged or engages a suddenly appearing enemy the contact report is sent as soon as possible.
In the latter scenario the reaction to contact for the SL should be as follows:
- Fall down facing your security direction.
- Orient yourself of the direction of contact.
- As soon as possible send a short contact report consisting as a minimum of "This is 1. Contact, contact. wait, out." and ideally direction (front, left, right, cardinal direction etc), range (close, middle, far, meters etc) and type.
Example: This is 1. Contact left, far, fireteam.
- Depending on the distance either go into position or assault the target (only if very close).
- Send full contact report and preferably include a suggestion for the next manoeuvre.
Common for all points are that the full contact report is to be sent as soon as possible. If you can send it while you throw yourself at the ground, you do it.