Lost animals are almost always shot placement issues and almost never bullet failures.
Deer are small, narrow, thin-skinned and light-boned. Almost any bullet that strikes the heart/lung vital area will have them dead with 150 yards at most.
My guess would be that you shot low or gut shot.
Trouble is, it's guess. Frankly, so are your estimates. We've all been there. I wounded one last week that should have been a gimme. I know where I should have hit but I have no idea where I did hit because we couldn't find her.
I also know, from talking to guys with dogs that track wounded animals, that the recovered animals are never hit where the hunter says they were/should have been.... It's kind of obvious if you think about it.... if they WERE hit there, they wouldn't need a tracking dog.
Still happily answering to the call-sign Peetza.
You do not HAVE a soul. You ARE a soul. You HAVE a body.
He is no fool who gives what he can not keep to gain what he can not lose.
-Jim Eliott, paraphrasing Philip Henry.