Deep Penetration For Compound Bows

The amount of penetration a compound bow can achieve depends on several factors, including the type of arrow used, the weight of the bow, and the strength of the shooter. In general, a compound bow can generate enough force to penetrate a human skull. Arrows come in different weights and sizes, and heavier arrows will penetrate more. The weight of the bow also plays a role: a heavier bow will have more power behind it, resulting in greater penetration. Finally, a stronger person will be able to draw the bowstring back further, adding more power to the shot.

Arrow weight and size

When choosing arrows for a compound bow, there are a few key considerations to keep in mind, namely arrow weight, arrow length, and arrow spine (stiffness).

Arrow Weight

Arrow weight is crucial and will depend on your objectives. For target practice, you'll want an arrow with a total weight of around 5 to 6 grain per pound of draw weight. So, for a 60-pound draw weight bow, you'd use arrows weighing between 300 and 360 grain. For hunting, you'd opt for a slightly heavier arrow, with a total weight of between 6 and 8 grain per pound of draw weight. In the case of a 60-pound draw weight bow, this translates to an arrow weight of 360 to 480 grain. It's important to never use an arrow that weighs less than 5 grain per pound of draw weight, as this will damage your bow and void the warranty.

Arrow Length

Determining arrow length is straightforward. Simply take your draw length and add 0.5 to 1 inch. So, if your draw length is 28 inches, your arrow length should be a maximum of 29 inches. This ensures the arrow is just long enough to clear the front-most part of the arrow shelf.

Arrow Spine

Arrow spine, or stiffness, is another critical factor. As draw weight increases, arrow rigidity (spine) should also increase. The International Bowhunting Organization (IBO) recommends using arrows with at least 5 grains of weight per pound of draw weight as a safety precaution. A bow with a 60-pound draw weight, for instance, should use arrows of at least 300 grains.

Bow weight

The draw weight of a compound bow is the amount of force required to pull the string back. This is measured in pounds. The draw weight is influenced by the stiffness of the bow's limbs. A bow with a maximum of a 70-pound draw weight will have stiffer limbs than a bow with a 60-pound maximum draw weight.

The draw weight is adjustable on most compound bows, usually by about 10 pounds. The marked draw weight on a bow is the maximum amount that the bow is capable of reaching. For example, a 70-pound bow will typically be adjustable from 60 to 70 pounds, and a 60-pound bow will be adjustable from 50 to 60 pounds.

The term "let-off" is used to describe the amount of draw weight required to hold the bow at full draw. This is measured as a percentage of the bow's draw weight. Many compound bows have a 75% let-off, meaning that when the bow is fully drawn, the shooter is holding back only 25% of the draw weight. For example, a compound bow set at 60 pounds with a 75% let-off means the shooter has to hold 15 pounds to keep the bow at full draw.

A comfortable draw weight is different for each shooter. Most adult males shoot between 60 and 70 pounds. Today's bows are extremely efficient, and 40-pound compound bows are more than capable of harvesting many big game animals. For whitetail deer hunting, anything above 40 pounds is fine. For larger game, such as elk or moose, a good recommendation is at least 60 to 65 pounds of draw weight.

A general rule of thumb is that a shooter should be able to shoot a bow about 30 times in a row without becoming fatigued. If the shooter cannot draw the bow 30 times, the draw weight should be decreased.

Shooter strength

The strength of the shooter is a key factor in determining the penetration of a compound bow. The stronger the shooter, the more power they can put behind the shot. This is because a stronger person will be able to draw the bowstring back further, adding more power to the shot.

When testing out a bow, try drawing it for 20 to 30 seconds without shaking. If you can do this, then the draw weight is a good choice. It's important to match the draw weight to your strength. If the draw weight is too hard to hold for a long time, it will impact your accuracy. Using a draw weight that you can hold easily will allow for a steadier and more accurate shot.

The strength of the shooter will also determine how well they can handle a bow with a shorter brace height. A shorter brace height will make the bow less forgiving, requiring the shooter's form to be "spot on". A stronger shooter will be able to handle this better and will benefit from the faster speed that comes with a shorter brace height.

Additionally, the strength of the shooter will determine how well they can handle the weight of the bow. A heavier bow will have more power and result in greater penetration. However, if the bow is too heavy for the shooter, it will impact their accuracy and shooting form. As such, it's important to choose a bow that matches your strength.

In conclusion, the strength of the shooter plays a crucial role in the penetration of a compound bow. A stronger shooter will be able to take advantage of a heavier bow and a shorter brace height, resulting in greater penetration. However, it's important to find a balance between power and accuracy, as the shooter must be able to hold the draw weight steadily and maintain good form to make an accurate shot.

Tuning your bow

Tuning your compound bow is essential to ensure accuracy and comfort when shooting. Here are some detailed instructions to help you with the process:

Locate the Limb Bolts:

Start by locating the limb bolts near the centre of your compound bow. These bolts are found in large circular knobs that attach the bow's arms to the riser, which is the central part of the bow.

Loosen the Limb Locking Screws:

Some compound bows have a second set of bolts or screws called limb locking screws. These screws hold the limb bolts in place, and you can usually find them on either side of the limb bolts. Loosen these locking screws with an Allen wrench or a separate screwdriver to allow adjustments to the limb bolts.

Adjust the Limb Bolts to Desired Weight:

Now, use the short arm of an Allen wrench (typically 3/16 size, often included with the bow) to tighten or loosen the limb bolts. Turning the wrench clockwise tightens the bolt, while turning counterclockwise loosens it. Adjust each arm of the bow to your preferred weight, ensuring you turn each bolt the same amount. Remember to adjust the tension equally on both limbs.

Test the Bow's Pull:

Once you've adjusted the limb bolts, secure the limb locking screws if your bow has them. Hold the bow as you normally would and pull back the bowstring to test the draw weight. If you're satisfied, you're done. Otherwise, continue fine-tuning until you achieve the desired feel.

Choose a Comfortable Draw Weight:

The draw weight should match your upper body strength. If the draw feels too heavy or tires you quickly, reduce the tension. While a heavier draw weight can provide more power, it's important to find a balance that allows for accurate and comfortable shooting.

Consider Your Usage:

Think about how you'll be using the bow. Hunters may prefer a heavier draw weight for better penetration, while competition archers might favour a lighter weight to minimise fatigue during repeated shots. Choose a weight that suits your specific needs.

Use Average Draw Weights as a Reference:

If you're unsure, you can refer to average draw weights based on age and gender. These averages provide a starting point, but keep in mind that individual differences exist.

Draw and Hold the Bow:

Draw the bowstring just short of full extension and hold it for about ten seconds. If you strain or struggle to maintain the draw, decrease the tension by loosening the limb bolts. You should be able to hold the bowstring taut just before reaching the "wall" (the point at which the bowstring can't be pulled further) without difficulty.

Identify Points of Highest Tension:

As you pull the bowstring, notice where you encounter the most resistance. Ideally, the highest tension should occur right before reaching the wall. If you feel too much resistance earlier in the draw, slightly loosen the limb bolts. Conversely, if the draw feels too easy, tighten the bolts for a more forceful release.

Tuning your compound bow is a personalised process that may require some experimentation. Always prioritise comfort, accuracy, and safety when making adjustments.

Stabilizer weight and length

Stabilizers are all about balance—balancing weight, vibrations, and torque. They are not essential, but they can help resolve problems and improve accuracy. The main factor in achieving this balance is added weight.

When choosing a stabilizer weight, it is important to consider your strength and endurance level. More weight does not always mean steadier shots, and too much weight can cause fatigue and even injury. If you want to shoot with a heavier stabilizer, you should work up to it. Most stabilizers have basic mass weights ranging from 12 oz to 19 oz (350 g to 550 g) before additional weights are added. Pro shooters may stack up to 30 oz of weight on the end of their long rods.

The length of a stabilizer is largely a matter of personal preference, but it should be chosen with the shooting environment in mind. Small stabilizers are typically shorter than 10", medium-length stabilizers are 10–15", and long stabilizers are longer than 16". Small stabilizers are best for archers shooting in confined areas like dense forests or a hunting blind, as they reduce vibration and noise and minimize the jump of the bow. They are also optimal for bowhunters embarking on long trips, as they are compact and less vulnerable to wind. Medium-length stabilizers are usually the best choice for a typical hunting situation in wide-open spaces, as they provide a good balance of weight stabilization and vibration dampening. Longer stabilizers are mainly used for weight balancing and are often used by competition target archers and Olympic archers. They are more vulnerable to wind, so they are not ideal for unpredictable or undesirable conditions.

Frequently asked questions