I hope you find it. 500 yds was a long shot. Unless you are very proficient at
shooting at that distance, and are VERY familiar with your gun and the various bullet weights, it is not advisable to take a shot that long, even if you have a good rest. The bullet drop is about 33-36 inches give or take a few. The bullet should have still been able to expand as it is designed to. It is a lighter bullet meant for deer sized game. I have seen too many people go for the bigger grain bullet, thinking it will make a bigger impact and shock value. Unfortunately the larger grain bullet is designed for larger game, and it will not expand properly in a smaller animal such as a deer, and only pass through without much deformation of the bullet at all unless it hits a thick bone. I think your deer is dead. Let us know when you find him. A dog is definitely the answer to finding him sooner. Like they said look for crows, buzzards etc. Unfortunately the coyotes will be looking for them also. The 30-06 is an excellent round. It is very versatile in that it can be loaded down to a 110 grain bullet up to a 220 grain bullet. It was used in both world wars and Korean "Conflict"
, Some amazing shots were made with it at a 1,000 yd.s and was effective even at that range, with a 148-150 grain full jacketed bullet. The .308 is what Carlos Hathcock used to effectively take out enemy targets, and the 30-06 which is .308 diameter is a hundred and some feet faster than the .308 used in the m14's.
Good luck.
Wayne