Sorry, I disagree, 'those basic physics' are wrong. ____FPE at impact does not = quarry received that _____FPE at impact. The only way it would is if the pellet stopped in the quarry. And the funny thing about this 'off button' is the i've shot the entire backs of skulls off of starlings with headshots and they were still alive(this is because the life support system is in the hind brain and midbrain, closer to the base of the skull/neck and not in the regular skull like on us humans), limping and running on the ground a little ways.
Like I also mentioned, this happens with my .22 cal Diana 54 running at 24fpe at the muzzle. Some of these impacts where at 20 yrds and if you do the math, that was around 19 fpe at impact. The trouble is, the pellet goes THROUGH the critter, it doesn't stop inside, so the critter doesn't receive 19 fpe. It probably only received 1-2, the rest of the energy cruised on at 700 fps for _____yrds. Almost ALL of these quarry were found with perfect location shots to the upper chest, through the neck, through the lower chest, etc... didn't matter, only a few would drop instantly.
Like I said, the moment the range stretched out to past 50 yrds, they dropped like they were hit by a 98 mph fastball. But the R7 would drop them at 25 yrds instantly, with almost never a limp away, ever. That's because the critter got almost ALL of those 6-7 fpe.