Figured I would insert a little bit of experience with the 143 grain ELD-X at very close range. I hunt Western Washington Blacktails more than anything. The bullet has performed very well for many people at long range, but my experience has only been close. In a hunting situation that can put you 20 yards from a deer, to well over a grand, it is nice to have a bullet that works well at all ranges. Here are my 2 experiences with close range shots with the 143 grain ELD-X.
First, an offhand shot at a stationary Blacktail Buck at about 20 yards. The bullet entered about 6 inches back from the crease of the shoulder, and absolutely exploded on impact. The jacket separated from the core, and was recovered well inside the deer. There was an exit wound about an inch in diameter, which was weird, considering the lead core must have been the only thing to exit.
Second, A chip shot at 76 yards resulted in a lot of trimming of the far side shoulder. The buck was quartered away, and was very tense. The bullet was placed just a tad forward, and nearly blew apart the far shoulder after impacting the bone. It had an incredible effect, and only a few chunks of copper were found in the meat during cleaning.
All in all, I can't say anything about the OP's experiences, but both of my deer died incredibly quick, and led to fast recovery. I will keep shooting them as long as they keep killing stuff.