Kinetic Energy



If two bows have the same arrow speed but one is 50-60 lb. draw weight and the other is 60-70lb. Draw height does this mean that that one is more powerful, or are they equal? I am planning on hunting deer, elk, and black bear. So I think I should have a powerful bow.


Arrow speed is dependent on a number of factors, only one of which is the draw weight of the bow. The draw weight of the bow can vary depending on a number of factors including draw length, and cam type. A moderate cam bow with draw weight of 55 lbs. at 30 inches, might shoot an arrow slower than a fast cam bow with a draw weight of only 50 lbs. at 30 inches. Arrow weight will also affect arrow speed. The lighter the arrow, the faster it will come out of the bow. However, a faster arrow will lose velocity at a more accelerated rate than a heavier arrow. In other words, a fast light arrow may be moving faster as it leaves the bow, but at 40 yards it may be slower than a heavier arrow out of the same bow. Remember that most bows list their speed by IBO and AMO standards. Each are different, and your personal draw weight, length and cam type will most likely result in an arrow speed LESS than either of these standards.

Much to consider. Another factor to consider when choosing a bow for hunting is kinetic energy. On smaller game, whitetails, turkey, antelope or mule deer, etc., kinetic energy is not that important. Any bow at 45 lbs. or better within 20-30 yards will do the job nicely, if the arrow is placed right. On bigger game however, Elk, Moose, even big bear, you need more energy to drive the arrow shaft to it's target - the vitals. Take a look at our kinetic energy calculator. It will give you some idea about speed and arrow weight. A lighter arrow will give you a faster flatter arrow flight, and as such is more forgiving of misjudged distance. However, the lighter arrow decreases your kinetic energy. For big game you want to be as close to 65 ft-lbs as possible. To get there you have to consider draw weight, draw length, arrow weight and the distance you will be shooting.

A lot of guys will buy a really high draw weight bow to increase their arrow speed. They will increase their speed, but I have seen too many guys with over powered bows unable to keep their shots on target. Always choose a bow you can shoot, comfortably AND accurately. We owe that to the game we hunt! I personally hunt with a high energy cam bow. I do hunt both Elk and Moose, so I use a bow in the 65 lb. range at my draw length of 27 inches, and I use a 2314 aluminum arrow. I limit my range and practice till my arms fall off!

Good luck.