Spine shots ALWAYS drop them right there. Luck? Not from a tree stand!

Texas heart shot seems to work about the same.

If you want them to drop right where you shoot them, they need to be hit on a major bone. Through a front shoulder, into the boiler room and hopefully out the other side.

I am talking from a pistol caliber. Rifle with the right bullet, one that transfers all of it's energy, usually is a different story.

That has been my experience anyway.