It didn't drop right away.
if you shoot him in the broiler room (lungs) he is more than likely not going to "drop dead" neck/spine shots and head shots will drop a deer in its track but it is not a shot i'd recommend...
the best advice i could give would be; practice with your rifle and get proficent, learn how to "blood trail" a deer, paying very close attention to where the deer was standing, and which way he headed when he ran off, also try to notice his reaction (if any)..when you shoot the deer take note of something he is standing close too, like an old log laying down, or a certian tree, when you arrive at that spot start looking for hair, bone, and blood, then proceed (SLOWLY!!!!) in the direction the deer was traveling, at this point you could be looking for specks of blood to a spray painted path, you could also be noticing leaves that are turned over, i have gotten on my hands and knees looking for specks of blood... go slow...
oh yea! after the shot give the deer around 30 minutes before you start looking, hard to do, but the last thing you want to do is push a marginaly shot deer. useally they'll pile up pretty close and bleed out fairly quickly... iknow i'm forgetting some points here which someone else will add.. but welcome to the forums and ask away.lot of knowledge here we all had to start somewhere