Here are examples of how first sight and first fire works. The first example will be a WWII scenario of two German Hetzers protecting a village while a troop of British tanks approach. The second example will be a 1983 era American M1 tank protecting the same village from a platoon of Soviet T-72s.
Example 1. Two Hetzers have positioned themselves in a small group of houses. They declare that they are unbuttoned, over-watching woods #2 and the other small group of houses. A British troop of three 75mm Shermans and one 17 pdr armed Sherman Firefly are setup in woods #1.
The situation: Two Hetzers are parked in alley ways in a small group of houses. British troop of 4 Shermans are in a small wooded area. There are about 750mm or game scale units (GSU) separating the two groups or about 1500 real meters. The British plan for the turn is to make a rush toward the railway station. Note - A GSU is just a millimeter, but represents 2 actual meters.
The British are poised for their move.
Hetzer models within 10mm of the houses are considered to be in or among buildings. Small alleyways or village garden walls mask them. Actual building models are superfluous. They are used to represent a general built up area. Sometimes we use gray felt squares under the house models to indicate a built up are as we do green felt for tree limits.
Turn 1. Both side order a cover of the area. No movement. Trying to spot the other guy. The range is 735 GSU. The four Shermans try to spot any Germans in the area. Unbuttoned stationary has a base 40 factors. Target in buildings (-10). Size -1 vehicle (-1) gives a 29 total factors. This makes the base sighting range of 325. The best score that could be obtained only results in a range two times this or 650. So no sighting of the Hetzers is accomplished. Likewise the Hetzers which are unbuttoned stationary start out at 40 factors. Less looking through or into foliage (-5) and into 1-25 of woods (-10). With the size of the Sherman being 1 (+1) gives a total sighting factors of 26. We don't need to look it up. If 29 can't do it 26 doesn't stand a chance.
Turn 2. The British troop is given a Rush order. They move a full speed (160) toward the railway buildings. Ending 575 away from the nearest German. The Hetzer section issued Cover orders. Spotting - The unbuttoned Hetzers have a base 40. Target moving (+15). Size 1 (+1). Giving 56 factors or a normal range of 2300. With a modifier of (+1) for an additional Hetzer spotting as a group the worse roll would result in the range of 1150. This is an automatic spot of the British tanks. However, Hetzers are too far away to get a first sight shot this turn. They must be within 400 GSU by rule 8.8.3 or within 50 of an over-watch point by rule 8.8.6 had they over-watched this particular woods. Neither is the case so they cannot fire first sight on these tanks. They must wait until the following turn to fire. British tanks attempt to spot but as they are moving unbuttoned, the range is too great to spot the Hetzers.
Turn 3. The British troop continues with its Rush and moves another (150) toward the enemy. In order to facilitate shot distances the starting point of the move and the mid point of the move is marked with a chit. The Hetzers with Cover orders elect to fire. Since their Rate of Fire is 7 they can fire in both the first fire segment and the third fire segment when stationary. Fire in the first segment must be at or before the midpoint of the move. This range is 500 away Fire segment 1 - First fire. The base to-hit number is 5 up to 500. Target vehicle moved at any range (+1). First shot at target beyond 300 (+1). Target size (size = 1) adjustment (-1). The result is a 6 or better is needed. Both Hetzers fire. Both miss. Fire segment 3. The Hetzers are permitted to fire again. This time at the closest range (425) of the move. The base number at 425 is 3. Moving target (+1). Target size adjustment (-1). It is no longer the first shot at these targets so there is no additional penalties. The number needed is 3. Both Hetzers again fire. One scores a hit the other doesn't. Location of the hit is rolled and it is a 1. This is a track hit. The damage factor of a 75mm APHE is 6, but on a track hit there is a -2 bonus to do damage thus the effective Damage number is 4. If a 4 or better on a D10 is rolled the track is broken. A 5 is rolled and the Sherman suffers a broken track. Since this happened at the end of the move rather than along its path Sherman is stopped at end of its move. A green chit is placed next to it indicating a broken track. At the end of the segment a D6 morale roll is made for the tracked tank. Track broken (+1) and broken while moving (+1) which totals 2. Thus if the D6 roll is a 1 or 2 the crew bails out. If it does replace the green chit with a yellow one. Sighting Firing Elements phase. The British tanks can try to spot their tormentors. The range now is 425. As they were unbuttoned in the turn the base spotting factor is 35. Target in buildings (-10). Target size adjustment (-1). Target fired cannons up to 82mm (+15). This totals 39. The range of 750. A variable roll of 3 plus 3 friends gives a 6. So the range is 750. The Hetzers are spotted.
Turn 4. The British troop issues a Bound order. This will let the Firefly hang back with the tracked tank while the other two Shermans hopefully will draw fire away from it. Movement - Two Shermans move full toward the enemy. Chits are again placed at their starting position and the mid-point of their move. Since all parties have sighted each other and remain in sight there is no need to go through the sighting again. Even though all tanks can claim to be buttoned-up they do not lose sight of their adversaries. Fire segment 1 - Both Hetzers and the Firefly and the tracked tank are permitted to fire. All fire and any damage is simultaneous. If a sufficiently high roll is made on any to-hit roll multiple hits can be scored. Fire segment 3. - Both Hetzers and the Firefly and the tracked tank are permitted to fire unless they were KO'd in fire segment 1. If a sufficiently high roll is made on any to-hit roll multiple hits can be scored. Fire segment 4. Both full moving tanks may fire, if they have not been KO'd previous to this fire segment. As they moved over half-movement they cannot score no multiple hits no matter high of a to-hit roll they make.
End of Example 1. Play would continue until either side is destroyed or forced to withdraw.