Moose are large animals but that does not mean you can aim just anywhere and expect to knock down your game. You have a responsibility as a hunter and a human being to kill your game quickly and with as little suffering as possible.
Ideally, the best is a broadside shot through the heart, which is also through both lungs. Use the rule of thirds for a broadside shot. Line up the back edge of the front leg and visualize the body in thirds. Aim up from the chest between one-quarter to one-third of the total chest height and you will be on the mark.
(This has been excerpted from Moose Hunting Tips: The Ultimate Guide to Moose Hunting).