The question of what is the most appropriate arrow weight for bows set to a specific draw weight is a common one. The difference between what may be considered a heavy arrow and what is too light for bow hunting can be an important ethical question.
Here is a good rule of thumb for setting up your arrow weight.
Grains / Pound
380 - 560
420 - 540
440 - 520
The weight of the finished arrow is a very important factor, particularly when the goal is to effect a quick and humane kill when you hit your target. Knowledgeable hunters are aware that the momentum of the arrow is far more important than the speed.
So the question becomes: what is the ideal weight for a hunting arrow when shooting a bow with a certain draw weight poundage?
The most common compound bow set-up uses a draw weight of 60 pounds so the following is an example of how you might set up your hunting arrow.
A sensible range to aim for when setting up your arrow to shoot from a 60 pound draw weight is between 420 – 540 grain (per table above).
This is a finished arrow which includes the broadhead, fletching, nock and, for many, an insert.
A Sample Arrow Build
Using a popular hunting arrow as a guide here, let’s assume we have a Carbon Express Piledriver DS Hunter arrow with 400 spine. Let’s say our arrow is cut to 29 inches in length.
The GPI of the shaft is 10.5 so the bare shaft weighs 304.5 grains.
If we were to add a 125gr broadhead to the arrow, 3 Bohning Blazer vanes at 6 grains each and a nock adding 2 grains you come up with an arrow weight of 449.5gr.
You may choose to add a 75 grain Bloodsport Brass Insert to the front end of the bow bumping up the weight to 524.5gr. Heavier insert options are available should you need to increase the FOC weight even further.
This set up would sit you nicely within the range of what many people consider is a good hunting arrow weight for a bow that is set at 60 pounds of draw weight.
It would be possible to set the arrow up to be even heavier with a 100 or 125 grain brass insert or, alternatively, selecting an arrow with a lower spine, say, the 350 spine.
Other factors such as the arrow’s FOC have not been considered in this example and this will be something that must be figured out as part of your arrow tuning process.
The result is going to be tough arrows that are going to provide you with the greatest level of penetration possible.
You're After Momentum Over Speed
Remember, as the game weight increases you should be aiming to set up your arrow towards the heavier end of the recommended range.
This is because the momentum is going to increase as the weight gets heavier.
The greater the mass of the arrow, the greater the momentum. When momentum is substantial it is going to prove very difficult to move the arrow off its flight path.