I stand corrected. If you do the trick with adding and removing letters to get a new "roll" in creative menu you actually get new random values. Tried it just now with 19.2
From the xml I can see the damage of a .44 bullet is 70.
The vulture has a fixed negative damage bonus of 2, so its average damage of a quality 1 DV is 68, and the random range is always 15% of base damage (70), so plus/minus 10.5. So the worst DV you can find is a gun with 57 damage and the best DV with still quality 1 could have 79 damage.
If you have seen a DV with 50 damage, congratulations, your game has pulled a fast one on you.
The worst quality 6 DV has a damage of 70/2= 35 more than the worst quality1, so is at 92, far from the 50-60 dmg range. Shows us a picture please, I think you have been misremembering this.