Taking the darkhorse 5811's initial Terminal Coefficient interpretation further
Quick 'rate of change coefficient' google spits out...(ROC - Rate Of Change)
"ROC is often used when speaking about momentum, and it can generally be expressed as a ratio between a change in one variable relative to a corresponding change in another; graphically, the rate of change is represented by the slope of a line. The ROC is often illustrated by the Greek letter delta (Δ)."
We can ignore the 'often used when speaking about momentum' but the rest are the droids we are looking for.
So we have to learn how to measure 2 things.
1. ROC of bullet speed in gel.
2. ROC of bullet SD in gel. (SD gives you 2 numbers, frontal area and mass)
You get that data and you'll be able to automatically put the energy number along the entire curve and no reason we wouldn't stick with ft/lbs. V2xMass/450240
Additional to that is we'd have the 'penetration coefficient' lol, in the SD and it's rate of change, there will be a direct relationship to curve/number on the penetration part alone which is SD and it's rate of change being measured would allow us to see that and how it applies to rate of work it puts out at each impact velocity. And maybe that's all we'd need to see to make it all comparable to each other?
The ROC of SD alone gives what information? Penetration AND Work. So maybe I was right in that it's Section Density Reduction Rate (or SD Coefficient) is going to be the 'BC' for terminal ballistics.
ROC of SD is X between;
3500-3000 fps
3000-2500 fps
2500-2000 fps
2000-1500 fps
Or every 250 fps you get the data?, then calculator spits ROC every fps in between the delta's. Gotta start somewhere, we need to figure out how to measure this ROC.
There's a lot of 'change' going on in that gel, over a very short distance, to create the 'result of work' which is all we've been focused on measuring and at single impact velocities here and there.
Fun to think about, kicking can down the road on what we could achieve with that data to assist all hunters in the world....with that data we'd find out the simplest way to boil that info down and the bullet may get a 'terminal number' (or two, and in all useful impact velocity windows) that can then feed calculator that spits out the depth/work profile right beside all the inflight data in our current ballistics calculators at every fps/distance since we have that impact velocity data already in those calculators to as far as we fill out parameters for on our inputs.
Just like in ballistics calculators we do the inputs and see where the bullet runs out of fps we know works for bullet family...with the terminal side of it and know where it actually runs out of steam for what we like rather than use fps as a 'rule of thumb' based on trial and error as we have been doing for a looooong time.
Are we cookin with gas yet?