i have only lost a blood trail once but it ended up being a chunk of his guts had pluged up the wound
i looked for an hour or so and found the deer about 45 yards from where the blood stopped
however by the sound of your post
SHOT IT IN THE SHOULDER WITH 243 AT 15 YARDS WENT A MILE AND THEN LOST BLOOD.
it sounds to me like you hit low in the shoulder damageing muscle and no bone and no vitals
at any rate it sucks for you and the deer