* This calculator and the resulting calculations are based on a theory that Old Grumpy Hunter has about what is the safe minimum arrow weight for crossbows. Old Grumpy Hunter based his theory on the vertical compound bows standards from the IBO & ATA. Vertical compound bows have for the most part a longer draw length and many a wider axle to axle width then most crossbows. Both the IBO & ATA do not address crossbow draw weights. Old Grumpy Hunter has a video (Grains Per Pound. or How Low Can You Go?) that explains how he came up with these gpp values. That video can be found here https://youtu.be/umK4potWG6I
The resulting calculations from this calculator are provided only for something for the user to think about.
The minimum grains per pound used in this calculator have NOT been tested in the field and are provided here only as a theory.
It is up to the user to use an arrow weight that is heavy enough to protect his/her equipment. Death By Bunjie nor Old Grumpy Hunter are NOT suggesting shooting arrows that are below the bow manufactures recommendations even if the results of this computer may suggest using a lighter arrow. If you are shooting arrows that are below the bow manufactures recommendations, you are taking full responsibility for any and all damages to your equipment and for any and all injures to yourself and others.
Always practice safe shooting and use equipment that is in good order.
This calculator and the resulting calculations are strictly to be used for ENTERTAINMENT PURPOSES ONLY!