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How do you determine the best arrow weight for your bow?
The question is answerable but there are a lot of things to consider here.
Determining the weight of an arrow to a modern bow is a trickier task than it looks at first glance. It has several factors involved that must be carefully considered.
There’s a lot of physics, some measurements, and math involved in this process. You also have other factors to consider, like the type of shooting you’re performing.
But no worries reader, this is where we come in!
We have compiled some ways with which you can select the appropriate arrow weight for your bow.
We believe that this will give you a better understanding of arrow weight and why it’s important.
Let’s dig in!
What Is Arrow Weight?
In layman’s term, arrow weight is the combined weight of an arrow and all attached bits, such as the tip and nock.
Normally the weight of the arrow is measured in grains, commonly expressed in grains per inch.
Common logic dictates that arrows having lesser grains per inch is good. Lighter arrows have more velocity.
But them being better is not always the case.
For instance, the Easton Axis’s 340 spine version weighs 9.5 grains per inch whereas the 500 shaft weighs 8.1 grains per inch. But the 500 shaft version, despite being lightweight, is weaker.
So, tuning can be a problem.
There are also other things such as spine rating and the type of shooting that determines your proper arrow weight.
Why Is an Arrow’s Weight Important?
An arrow, when shot from the bow, carries kinetic energy.
The energy is produced by drawing a bow. When the archer shoots, that kinetic energy is then transferred to the arrow.
The weight of the arrow is crucial in determining the arrow’s velocity, drop rate, and whether it penetrates the target and how far.
Every kind of archer, whether a newbie, a hunter, or a competitive professional, tries to increase the performance of their arrows by using different weights.
Your arrow can be too light, too heavy, or just right.
Lighter arrows fly faster, which is great for striking a prey animal before it moves. However, they’re very hard to tune and can lack penetration.
On the other hand, heavier arrows can resist the wind better and have greater penetration but they are slower and will drop more.
An arrow that’s properly weighted to your bow will fly swift and true, and will be more accurate than a poorly-weighted arrow.
In extreme cases, if you use an arrow that’s way too heavy or light for the bow, it can severely damage the bow and even harm the archer.
We’ve seen arrows shatter because they can’t handle the sudden dump of energy1!
This is the reason behind the fact that manufacturers design bows for particular arrow weights.
Tips on How to Determine Arrow Weight
The first step to determining your bow’s best arrow weight, you need to know the length of your arrow.
A properly tuned arrow length depends on your draw length, so let’s start there.
1. Measure Your Draw Length
If you have a bow then it’s easy to measure your draw length.
The easiest way is to use a draw length indicator arrow and draw your bow with it nocked.
You can do this with a normal, long arrow, too, if you have a friend standing next to you to mark the arrow where it passes your front knuckle.
In case you don’t own a bow and you don’t know anyone who has one, you can use some math to calculate your draw length.
In order to measure your draw length, you need to follow some steps. You also need a measuring tape and preferably a person to just help you out.
The steps are given below:
- Stand straight. Make sure to not wear any clothes that can restrict the movement of your arms.
- Now, you need to spread your arms to the sides. You need to ensure that they form a straight line. Your arms should be parallel to the floor.
- The third step is to get someone to measure your entire wingspan. You need to measure the from fingertip to fingertip.
- Finally, take or convert your measurement in inches and then divide it by 2.5. The resulting value is your draw length.
2. Calculate The Arrow Length
Selecting the proper length for your arrow used to be a complex task back in the days
But nowadays, since arrow technology has somewhat improved, the process has become much simpler.
You simply take your draw length and add 0.5 to 1 inches to determine the arrow length that suits you.
So, if your draw length is 27 inches then you need to add a maximum of 1 inch to get an arrow of length 28 inches. You can buy an arrow that long or cut one down.
This will provide you with an arrow that will be long enough to clear the front part of the arrow shelf.
You need to remember that the length of an arrow is measured from the deepest area of the nock groove all the way to the end of the shaft.
The measurement doesn’t include the length of your broadheads.
3. Understand Grains Per Inch (GPI) and Grains Per Pound (GPP)
GPI and GPP, although they sound, the same are actually different things.
They are properly described below:
Grains per inch is the standard to measure the weight of an arrow shaft, excluding tip, nock, and vanes.
GPI is a linear measurement that’s irrespective of the diameter and thickness of the arrow.
Arrow manufacturers provide the GPI measurement for their shafts and it’s sometimes marked on the arrow itself.
In terms of GPI, arrows can be classified as:
- 5 to 6 grains per inch: Light Weight
- 7 to 9 grains per inch: Midweight
- More than 10 grains per inch: Heavyweight
Grains per pound is the ratio of the arrow’s total weight to the bow’s weight.
GPP is often confused with GPI but these two things are completely different.
The GPP total includes the arrow’s shaft weight, the weight of the nock, insert, point, and fletchings, and depends on the bow you’re using.
In terms of GPP, arrows can be classified as:
- 5 to 6.5 grains per pound: Lightweight
- 6.5 to 8 grains per pound: Midweight
- More than 8 grains per pound: Heavyweight
4. Calculate the Arrow Weight
Now we’ll figure out the weight of the entire arrow, from tip to shaft to nock.
All of those products should have their weights listed.
Multiply your shaft’s GPI by its length. Then add the weight of those other components.
This is your arrow weight.
You can reverse engineer this result by subtracting the weight of your non-shaft arrow components from a target arrow weight and dividing the result by your arrow length to calculate the needed GPI.
But how do you figure out that target arrow weight?
5. Select the Right Arrow Weight
Your target arrow weight depends on the goal you’re trying to achieve with your arrows as well as your bow’s weight, which is why GPP is important.
If you are a newbie and you just want to shoot arrows for fun then this is for you.
Your arrow weight when shooting targets should be around 5 to 6 grains per pound of the bow.
So, if you have a 60-pound bow, you need an arrow that weighs somewhere around 300 to 370 grains in total.
With a 100 gr field point, 5 gr nock, and fletchings that weigh 25 gr for a combined weight of 130 grains, your arrow shaft should weigh 170 to 240 grains.
If your arrow length is 28″ then this results in a GPI of 6 to 8.6 to hit your target arrow weight.
If you are a hunter, you want to ethically and reliably kill animals with your arrows.
So, you need arrows with greater penetration.
Here, you would probably need to get an arrow that weighs in between 6 and 8 grain per pound of the bow for whitetail hunting2.
So, for a 60-pound bow, you’d want an arrow that weighs around 360 and 480 grains.
Broadheads tend to weigh more than field points.
Following the above example, with a 150 gr broadhead your components would weigh 180 grains.
So, your shafts would weigh 180 to 300 grains, or 6.4 to 10.7 GPI with a 28″ arrow.
In real life, you may not want to buy separate arrows for hunting and target practice because you need to consider cost, too.
So, what you can do is get arrows that weigh about 6 or 7 GPP, or at least between 5 and 8 GPP.
6 GPP lets you accomplish both activities without compromise.
One thing you should consider is not to buy an arrow that has a weight of less than 5 grain per pound of your bow’s draw weight.
Using such a light arrow may void your warranty and, in the worst case scenario, break the arrow, damage your bow, and shower you in high-velocity arrow debris!
Wooh! Does this seem a bit overwhelming?
It can seem that way at first, but it’s not bad once you understand the math involved.
We believe knowing these tips will help you a lot in deciding the right arrow for your bow.
Note down your requirements, match that with your components, buy the right products, then enjoy shooting!