Low Kinetic Energy Setups
Posted By
Scott Wiegel
at
12/17/2009 12:00:00 AM
Filed under:
midwest whitetail ilbowhunting
Low Kinetic Energy Setups
I have been asked many times in the bow shop what works best for a situation where you have low kinetic energy. For purposes of this paper, a low kinetic energy setup is one that is generating less than 50 ft-lbs of kinetic energy. And remember – these are opinions. There are other ways to ‘skin a cat’ so to speak.
Arrow weight, and distribution of that weight, is important. You must have a relatively heavy weight arrow to get good penetration. And penetration is critical when you are trying to kill an animal with a low kinetic energy setup. I would recommend something no lighter than 8 to 9 grains per pound of draw weight. So for a 40 lb compound bow, an arrow no lighter than 360 grains is appropriate. This may seem heavy – and will definitely slow the arrow down – but it will allow the bow to put more energy into the arrow during the shot. I would not shy away from arrow setups for kids that were in the 10 to 11 gpp area – especially if the extra weight is put into the field point / Broadhead. I have no scientific proof of this, but it just seems that arrows with more weight up front out perform an arrow with the same weight – but distributed in the shaft. So for a 360 grain arrow, a 100 grain tip is appropriate. If you want to really push the weight up, then go for a 400 grain arrow with a 125 grain tip. This is a devastating combination out of most 40 lb bows that we sell.
Another topic is broadhead selection. Because of the low kinetic energy, you need a broadhead that will punch through an animal quickly without much loss of energy. For this reason, you need to stay away from mechanicals. I would also suggest staying away from a chisel or Trocar tip – they are great for smashing bone when you have a high kinetic energy value and a slightly bad shot – but do little good when you have no energy to spare. That limits the selection to fixed blade broadheads with cut-on-contact tips. The next thought on broadhead selection is the number and size of blades. The more blades and the larger the cutting diameter – the more energy required to shoot through a deer. Many traditional archers shooting longbows will select a two blade broadhead with a cut-on-contact tip – an excellent choice for a low kinetic energy setup.
Final topic is shot placement. You must avoid any major bones such as the shoulder blade (scapula) or spine when you shoot. This necessarily limits your shots – you must pass on any shot angle that requires penetration of major bones or muscle groups. I am not sure of the exact value – but it does take a lot of energy to drive a broadhead through something like a leg or shoulder bone. On an animal the size of a deer, the rib cage along the side is very thin and relatively easy to penetrate. The lower in the rib cage – the thinner the ribs (and thus easier to penetrate). If you have an old deer and are forced to shoot high in the rib cage (for example, due to a severe downward angle from a treestand) – it is going to take a lot more energy to penetrate. This is due to the simple fact that where the ribs attach to the spine – they are very, very thick. Excellent shot placement with a low kinetic energy setup requires that you shoot the animal low in the rib cage (a heart shot is a great shot).
We have kids shooting low kinetic energy setups successfully on deer every year. You just need to build the right arrows and then place one in the right spot. It will work every time and leave you with short blood trails!
