Tom,i have shot a few crocs. including a 13 footer with my.270 using 130 gr.bullets.Shot placement was just behind the neck.Rifle was firmly placed and there was also a backup gun in case the croc. was injured and started to head towards the water.Distance was about 25 yards.There are a few lakes here right in the middle of the desert with large sand dunes enabling one to crawl behind them right up to the croc.