Re: .243 bullet weight 100 or 110 gr.
I agree with Chris , asd long as you can hit and tear up a major organ the deer will die.
shot placement is the key and if you do make a bad hit leave the deer alone , he'll bed down close and expire.
I shot a large 6 point with my bow last year , the arrow hit a small vine that I diden't se and deflected the arrow , he was hit far back and quartering away. I knew it was a bad hit so I waited about two hrs then snuck out of my stand and came back in the morning , the deer was dead less that 100yds from where he was hit.