Going on memory here, but if I recall correctly the intended behavior is that rate of fire, turn speed, and reload speed all decrease linearly with health up to a (theoretical) 50% of base at 0% health.
So a gun at 50% health should fire and reload at 75% normal speed.
Well, from what I have here, it's either the fluctuations of lag or whatever the factor here is are incredibly similar each time, to a degree that it looked like a more interesting pattern than linear, or something here is really wrong. Because as far as I know, there are not too significant error bars in my measurements here...
I will look further into rate of fire now, just to check it too, I fear it will not have that accurate results though considering you don't have many guns with rate of fire of more than about 1.5 seconds like the mercury... I might just record at a much higher framerate for it.
there is not really any reliable way of measuring turning speed accurately, so I will not bother with that.
I am encouraging other people to try and measure reload times with the same methods I did of chem spray on gun so it won't catch fire, and then F6 it for 12.5 damage. I found that the most accurate way to measure the time is via recording and counting the frames it took for reload. - Who knows? maybe you'll be end up more successful in proving the relations between gun HP and said behavior.