When to take a shot is always a question of ethics, and a personal decision of the shooter. Capability is not always the deciding factor. There are many shooters that are capable of hitting a target at longer ranges if the conditions are right. Go to the benchrest competitions and meet some of the real shooters. Some (I believe most) of them do not think game animals should taken unless they believe that the shot is certain to take the game quickly with the least amount of pain.

I believe that everyone can agree that a super accurate rifle and top quality scope are minimum requirements for consistent long range shooting. Although I am sure there are exceptions, lightweight factory rifles are simply not good enough for consistent long range work.

The OP did kill his deer, good for him. I certainly would not brag about the placement of the shot. I do not think videos of deer with broken backs are good for the image of hunters.