Yes, a 50# bow is enough to take a deer with. I know a lady that took a 2000 lb. African Eland (african antelope) with a 46# bow. As for max range, you need to stick within your own personal effective range. The best thing to do is to start practicing and then find out at what range you are placing all of your arrows into the appropriate target. For whitetails that should be in a 6 inch circle. (Approximately) For mulies it should be around 8 inches and for elk you can go from 12 to 16 inches. Make sure that the limbs and cams (or wheels) and string are all in good condition before you start shooting. If you are a first time shooter, I would also recommend that you use an arm guard. Good luck!!