Whilst the d20 System and Redline have pretty much all the rules you need, the basic rules don't really deal with automatic weapons - well, being a fantasy game, it wouldn't! So here are the couple of additional rules needed for the modern world.
Some weapons are capable of spitting out many more bullets than a single shot revolver, and the more bullets you fire, the more bullets you have that are capable of hitting the target, scoring more damage.
A weapon capable of firing in burst mode fires five bullets per pull of the trigger.
Burst fire allows two chances to hit the target, each capable of scoring full damage.
A weapon capable of firing in fully automatic fire uses 10 bullets per pull of the trigger. Fully automatic fire allows for three chances to hit the target, each capable of scoring full damage.
If a weapon doesn't have the required bullets left in the magazine, then it may not fire in burst or fully automatic mode.
Telescopic scopes function exactly as their Dark Future counterparts
- divide the range to the target by the rating of the scope (or 1.5 for rating 1 scopes).
Laser sights gives a +2 modifier to hit the target. The other sights simply negate any darkness penalties.