QUOTE (The Jopp @ Aug 9 2010, 03:13 AM)

So a running gunbattle and a sprinting shooter trying to hit a dodging and sprinting target have a base modifier of -6D6
Arsenal actually already has optional rules for Attacker Walking (-1, page 161).
And, uh, i don't know what you guys are talking about. 4a Has modifiers for running for both the attacker and defender:
Running modifers, 149: -2 to all tests except Charging and Defending.
Attacker running(150): Ranged Attack Modifier -2
Defender running(159): Ranged Attacks Modifier: +2
Somewhat related: Charging is a Melee modifier, +2, and doesn't suffer a movement modifier for running. Someone recieving a charge(if they choose to. The wording is ambigous) gets +1.
The modifiers for running are -both- for attackers and defenders. Its one of the reasons Gyromounts(limbs, mostly), Gyroharnesse(worn), and Gyrolinks(for vehicles) are so good. They let you run, keep the defensive bonus, and not suffer the offensive one.
That being said, i like your table. It makes sense.