If your hunting deer, IN MY OPINION there is no crossbow that is good to 50 yards with possible further shots. A crossbow has the effective range as a compound, 30 - 35 yards for deer. The time it takes for the arrow to travel out to 50 yards a deer can easily move over half it's body length, putting the arrow into a non lethal shot, or better yet, a complete miss. Even if a deer does not react to the shot (sound of bow or arrow), the normal actions of a deer (walking, turning ect) can move the deer far enough for a bad hit.

Todays crossbows can hit accurate well out there, past what you are looking for, but these are on a fixed target. You have no control of the actions of the deer and if it moves after you release the arrow. If you are determined to shoot deer at 50 yards, archery is not the tool for you.