The formula made slightly more sense, in the fact that it wasn't entirely random. It basically started with the weapon's strength, plus a D6, and then started adding on additional dice depending on what it was. For example, a lascannon was 3D6 + 9 (can't believe I still remember that). The one thing those AV numbers did do was make it nearly impossible to damage a vehicle with certain weapons. The was no throwing piles of shots at something and glancing it to death. You could unload as many multilasers at a vehicle as you wanted. You weren't doing anything to it.