How Does a Compound Bow Work?

The magnificent compound bow has been attracting praises left, right, and center for the last few years.

Indeed, for many enthusiasts, the compound bow is the single most revolutionary invention in the entire archery industry over the last century.

But exactly how does a compound bow work?

Or rather, what makes these bows different from your traditional bow?

Well, this is what we will be discussing in this article.

We will be explaining the technology, the overall construction, the accessories, and how everything works in a modern day compound.

Compound bows trailblazing technology and how it works

Now, the reason why these bows are rated as the most robust, fastest, easiest to use, and most accurate bows to have ever graced the face of the earth is because of their futuristic technology.

I will highlight the most revolutionary components next in the design and how they work.

Pulley/cam system

Compound bows use a unique levering system to help you shoot powerfully and with excellent precision.

To this end, the bow comes with big wheels mounted on the end of each limb.

The cams work in tandem with the cables and pulleys to maximize your drawing efficiency in the range (more on this shortly).

How does the pulley/cam system work?

Like I hinted, the role of the cam systems is to optimize the energy that the bow stores as you draw it and eventually create a let-off at full draw.

Let-off simply means you’ll be holding less poundage at the end of the draw cycle.

Let me explain further..

To begin with, all bows shoot by storing energy in the limbs and then ultimately transferring it as kinetic energy to the arrow at release.

And in traditional bows, this energy is stored and transferred directly.

But because of the innovative design of the pulley/cam system, a compound bow stores this energy more ‘economically’.

Specifically, the system creates leverage (thanks to the mechanical advantage) which helps store the energy in the curved limbs when drawn.

The compound bow limbs are more rigid (they’re made of stiffer materials) than those of recurve bows or a longbow so they’re more ‘productive’.

In fact, standard compound bows stores nearly double the energy of recurve bows with equivalent peak draw weight.

They can hence propel your arrow at staggering speeds –some models are advertised to exceed 340fps.

What about the let off?

Traditional recurve bows have linear draw weight curves.

This implies that the draw force usually becomes heavier the further you draw it back towards your face.

The bow is thus most difficult to hold at full draw since it has attained its heaviest draw weight. 

This is quite contrary to what happens with compound bows, again thanks to the lever system and mechanical advantage.

They actually become lighter (and easier to hold) the more you advance the draw.

That’s because the unique leverage enables it to reach peak weight within a few inches of the draw.

The compound bow weight then remains perfectly balanced until the end where its cams let-off, making it significantly lighter.

The let-off can make a massive difference as it can reduce the weight in your hands by as much as 85% when fully drawn!

This allows you to relax and better concentrate on your target.

Adjustable draw stops

Another fundamental contributor to the extraordinary performance of compound bows is the design of the draw stops.

Now, the pioneering pulley system typically includes rubber-covered blocks that provide a pretty solid “back wall” to draw against.

The biggest news is that they’re micro-adjustable so you can easily make desired adjustments to get your perfect draw length.

This helps you enhance the accuracy of shots since you can maintain consistent anchor points.

The accessories that make compound bows different and how they work

In addition to the aforementioned key parts, manufacturers have released a couple of accessories that help improve the overall functioning of these bows.

Let’s meet them:

Mechanical release aids

Many compound bow enthusiasts prefer using a release aid to hold as well as to release the bowstring instead of bare fingers.

This device usually attaches to the string near where the arrows attach (just below the nocking point) and ease the pressure on your fingers during the draw cycle.

Using a mechanized release aid delivers a more consistent arrow release than fingers as it reduces the arrow oscillation.

This allows you to repetitively shoot accurately.

Release aids also help eliminate target panic (aiming problems caused by irregularities like shaking, moving, and fidgeting), a common issue even among experienced archers.

Sighting system

Compound bows sighting system is quite sophisticated.

There’s first a “peep sight” (a ‘hole’ in the bowstring) to let you adequately sight your target.

This helps you narrow in on your sight picture besides cutting off outside distractions.

That aside, the bow has a front sight installed along the riser.

This supplies additional accuracy through magnification and picture alignment.

In terms of construction, modern front sights use “pins” while others use the more advanced laser technology to give you a better view of targets.

The range finder completes the “sighting equation”.

Its role is to help you calculate the range more accurately, greatly boosting your chances of hitting big bucks with a compound.

Stabilizers

Stabilizers in compound bows have several crucial functions.

They, first and foremost, absorb vibrations at the shot, effectively minimizing the shock you feel in your hands on the grip.

This noise dampening is one of the reasons why these bows are quieter.

And just before we move on, I should add that you can always purchase and install a powerful silencer if you want to it dead silent.

Moving on, a stabilizer introduces some extra weight making it more balanced. If you have ever shot a rifle, you know that a heavier barrel is more stable to aim with.

This aiming stability is again critical for consistency in shot execution and form.

And the heavier the stabilizers, the better for the bow.

That’s why archers competing in the World championships and the Olympics favor bows with very heavy stabilizers.

Does dry firing a compound bow ruin it?

Dry firing is shooting an empty compound bow (no arrow onto the string).

Now, because of the constantly high tension in compounds and their many moving parts, compound bows can be damaged extensively by a dry firing incident.

Like we had said, the stored energy is usually stored on the flexed limbs before being shifted to the arrow so the arrow serves as a ‘release’.

And so in the absence of an arrow to absorb the released energy, it will ‘escape’ through the bowstring and its limbs causing significant structural destruction to the entire bow.

The limbs may crack while the axles might bend. The string will also probably derail. You might also experience cable slide failure and cam warpage.

In extreme cases, the bow completely shatters!

Worst of all, the broken parts could end up in your eyes and blind you!

No wonder all pros sternly warn against the practice.

How to get more out of your compound bow

Whether you’re using your compound for target practice or hunting (professionally or as a hobby), you can get more out of your bow if you know how to tune it.

For starters, tuning a bow involves two aspects:

  1. Cam’s timing
  2. Center-shot alignment

Let’s see how.

a. Check the cam’s timing

If your bow cams’ aren’t properly timed, they will fail to rotate in sync and won’t reach full rotation simultaneously.

You thus feel as if the bowstring is pretty loose and the bow will no longer shoot with its previous efficiency.

To correct this, check your bow’s manual for right timing details then inspect the bow to see if the current placement is correct.

Don’t hesitate to seek assistance from your archery club or local archery shop if you are struggling to set the timing.

Having said that, timing is not a big issue for single-cam compounds.

Nevertheless, you should still adjust the timing marks if you find them off as per the manual.

b. Work on the center-shot alignment

Your accuracy will be outstanding if you are shooting your arrows from the perfect center.

The good thing is that you can easily tell if your bow is ‘perfectly-centered’

You simply inspect if your arrow is pointing straight towards your target before taking a shot.

If you notice your nocked arrow pointing to the left/right of the target instead of directly, then the bow has a misaligned center-shot and you need to work on it.

This will need you to adjust the rest/nock placement until you obtain a clear center-shot.

There’s no specific formula to use so keep adjusting the two settings until it’s congruously aligned.

Again you can ask for help from the pros.

Issues with Compound Bows

Nothing is faultless and compound bows aren’t an exception.

Here are some complaints against this famous bow.

Costly

If you have been impressed and planning to get one, it’s worth adding that compound bows generally cost more than longbows and recurve bows.

While on the whole you can get brilliant longbows and recurve for only $150 (and less), a decent compound bow can set you back as much as $500.

The high-end models will force you to dig even deeper since the price can rise even beyond $1,000 depending on the brand name and features.

Maintenance is a big headache

Because of their countless moving parts, the bow is more susceptible to malfunctioning than traditional bows.

And you have still have to spend big because most of the parts don’t come cheap.

Are compound bows good for beginners?

Sure, yes.

In fact, compound bows are the easiest to aim and shoot for novices because they require less force to draw due to their High-Tec construction.

I hope you also recall the let-off factor.

Even better, some manufacturers have designed a variety of beginner-friendly compounds so there are incredible options for first-timers.

Recap

So, how does a compound bow work in summary?

Well, the most remarkable thing about the bow is its pulley/cam levering system that grants you a mechanical advantage during the draw cycle.

The stiff limbs are also pivotal to the operation since they make the bow more energy-efficient compared to other bows (less energy is wasted in limb movement).

The bigger cams and their different weight profile and manipulation when you start pulling the string eventually gives you as much as 85% “let off” at full draw.

You can hence hold the bow for longer at full draw as you search for the perfect shot.

The construction also gives a steadier grip for a more accurate shot.

That’s why they are considered the kings of archery today.

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