Are fixed damage weapons worse than damage range weapons?

Solution 1:

My impression is that the list is sorted by maximum damage first, then by minimum damage. The minimum damage value is used as tie breaker. It just happens that, for fixed damage weapons, the minimum and maximum damage values are the same.

If you invert the min/max damage values for each weapon so that the max value is shown first, and represent fixed damage as a min/max range with the same value repeated, we get the following list:

Enhanced Sawed-Off Shotgun: 8-6
Rusty Laser Pistol:         7-7
Sawed-Off Shotgun:          7-6
Enhanced Hunting Rifle:     7-5
Rusty Sawed-Off Shotgun:    6-6

According to this interpretation, the rank of a weapon does not depend on whether it is a fixed or range damage weapon. It just depends on its max/min damage values.