Advanced Rules by Steven Rushing
http://ourworld.compuserve.com/homepages/swrushing/2001.htm
A character may spend extra time to gain accuracy against a specific target. This may be called getting Set in HERO or taking Aim in Fuzion. A character may gain a +1 for each full action he spends aiming at a target up to a maximum of +3. The target must be specifically determined and within sight of the aiming character.
The benefits of aiming extend beyond the simple bonuses to the die roll. In some cases benefits of gun sights or scopes are only applicable with the aiming maneuver. The greatest benefit would be the ability to gain better damage by hitting specific locations on the target.
When a character fires an aimed shot, s/he applies the bonuses not only to the general to-hit roll but also to reduce the hit location penalties. thus, for the purposes of hit location shots, s/he gains TWICE the benefit.
EXAMPLE: A character aiming for two actions gains a +2 bonus. She wants to specifically target the arm in order to minimize the chance of killing the target but disable his offensive capability at the same time. The normal penalty is a -3. The aiming bonus reduces this to a -1 AND adds a +2 to the roll, resulting in a net of +1.
This requires the use of the called shots rule for aimed attacks. The GM could simply rule that called shots and hit locations ONLY apply to aimed shots. Normal unaimed fire does not gain any particular hit location. Alternatively, the GM can use the normal called shot rules for unaimed fire and aimed fire. In either case, the bonus for aimed fire listed above might apply.
Alternative hit location "groups" from HERO 4th should probably be added into Fuzion for this advanced level of detail. These include : Head shot at -4 (1d6+3 loc), High Shot at -2 (2d6+1), Body Shot at -1 (2d6+4), Low Shot at -2 (2d6+7), and Leg Shot (1d6+12).
As a much simpler version on all this, a GM could simply grant aimed shots a +1 per die damage bonus for each +1 of aiming bonus and disregard the actual hit location charts. After 3 full phases aiming, the character would nearly double his average damage, similar to the effect from hitting a vital spot.
The net result of these rules will be that characters who take an extra phase or two to aim at their target will find in general more control over their damage and greater damage due to shot placement. A greater differentiation will grow between "firepower" specialists who fire with every action and marksmen who take far fewer but more deadly precision shots.