Is your bow faster than a deer? Speed Bows vs. Bow Noise

 

Throughout my years as a bowhunter, I have found fewer things that agitate me more than absurd claims by bowhunters.  The one claim that is most irritating to me, “My bow is so fast, deer can’t jump the string.”  That would be excellent if it were true, unfortunately, it’s physically and mathematically impossible.  Let us take a look at the numbers and action photos that shoot the, “speed theory” out of the air.

 

The bows on the market today are undoubtedly the fastest bows that have been produced and while they can send arrows down range at speeds over 350fps, they still aren’t faster than a deer’s reaction time to the sound of the bow.  Humans have a simple reaction time that has been measured at about .15 seconds, this is the time it takes from hearing a sound to having a reaction movement to the sound.  While it is extremely difficult to measure exactly a deer’s simple reaction time, it is fairly simple to calculate that it’s faster than that of a human.  For the sake of the discussion, we will use the fastest bow and the slowest deer for our calculations.  Keep in mind, my Mathews z7xtreme is slinging an Easton Axis 340 arrow tipped with an NAP Spitfire Max at 299fps.

Here is our hypothetical scenario:  A shooter buck strolls by and stops at 30 yards (90 feet) in your shooting lane.  You hold your pin on the lungs and touch the release, the buck drops at the sound of the bow and your arrow sails over his back.  This past September I had a similar scenario except the deer was a doe and my arrow spined her as opposed to missing altogether.  The distance was exactly 30 yards, my mistake here was not holding my pin on her heart.

With the speed of sound at 1,126fps (768mph) and an arrow moving 350fps (239mph), this means the sound of the bow arrives at the deer almost three times faster than the arrow.  What does this mean to us as bowhunters? This means (with our given scenario) that our arrow reaches the deer in .257 seconds (90fps/350fps), and that the sound of the of bow reaches the deer in .08 seconds (90fps/1126fps).  Subtracting these values gives us the the amount of time the deer has to react from hearing the sound to the arrival of the arrow, at 30 yards, the time for reaction is .177 seconds.  As we discussed previously, the slowest deer on the planet (or a human) needs less than .15 seconds to react to the shot.

These are a series of photos taken from a previous Bowhunt or Die episode of a deer I shot in Wyoming.  I marked my aiming point with the yellow dot, throughout the photo progression the dot stays constant and you can see the movement of the deer throughout the shot.

In this photo, you can see my lumenock in on it’s way and the deer hasn’t reacted to the sound of my bow.

The arrow is roughly 2/3 the way to the deer and she has already dropped several inches.

In this final photo, my lumenock has disappeared behind the yellow dot which represents my initial aiming point.

Conclusion? Myth Busted!  Even with one of the fastest bows on the market and the slowest deer on the planet, your bow does NOT shoot an arrow faster than a deer can react to the sound, period.

Fortunately for us as deer hunters, this doesn’t mean every deer will jump the string, and if they do, it won’t be enough to completely dodge the arrow.  This knowledge is obviously… just knowledge unless we apply it to our hunting situations.  For me, it means, shoot for the heart.  I hold my pin on the heart and if the deer reacts to the sound, my arrow should find the lungs.  If the deer does not react and my shot is on target, my arrow will find the heart.

Dustin DeCroo

Dustin DeCroo

Hunting Guide at Big Horn Outfitters
Dustin DeCroo

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Comments

  1. Rudy L. says:

    Not so fast … !
    First, you state 3 different values for typical “reaction times” .
    A. .177 seconds @ 30 yards for deer
    B. .15 seconds for the slowest deer [or human] on the planet
    C. Humans [or deer] require < "less than .15 seconds to react"
    Which is it ?
    Because value "B", being [ 0.15 sec] , is actually a quicker reaction time; not slower than value "A "for the slowest [deer/human] on the planet than 0.177 sec.
    Secondly, you state 2 different arrow speeds.
    You claim todays bows are the fastest ever, exceeding 350+ FPS.
    Then you utilize a "Matthews" Z7 Extreme quoted at a meger 299 FPS to prove your impossible to jump the string example at 30 yards.
    A 51+ FPS variation makes a huge difference in proving your point or not.

    Let's revisit the facts:
    Sound travels at roughly 1125 FPS
    Lets utilize 33-1/3 Yards for the distance. [ 100 feet ]
    Using an Excalibur Micro 335 chronographed at 333-1/3 FPS.

    Sound travels 100 Feet in 0.0889 seconds [0.9 or 9/10, nine-tenths of a sec.]

    Arrow travels 100 Feet in 0.300 [ .3 or 3/10, three-tenths of a sec. ]
    In 0.10 or 1/10 of a second the arrow travels 33-1/3 Feet … !

    Sound time value of 0.0889 sec. + Reaction time value of 0.177 sec= 0.2669 [ 0.267 sec. ]seconds. This is the time it takes the sound to travel 100 feet PLUS the reaction time for the deer to begin to move.

    Recalling the arrow travel time at 0.300 sec. minus the Sound travel time + Reaction time value of 0.267 sec. leaves ONLY 0.033 seconds [33/100] to begin to move out of the path of the arrow.

    Utilizing an"Excalibur" Matrix 380 rated at 380 FPS requires only 0.263 Seconds to traverse 100 Feet …

    … 0.267 Seconds sound/reaction combined time value MINUS 0.263 Seconds leaves only 0.004 Seconds [4/1000] for that shooter Buck that strolled into your lane to make his move to dodge your arrow.

    Today we have crossbows exceeding 400-425+ FPS ……

    Conclusion:
    That wise old Buck had better do his best on his first move because HE has met his match and probably "Maker" .

    Todays equipment IS fast enough to eliminate any deer from jumping the string.

    Reply
    • D bentley says:

      Your wrong about the bow being faster than the deer. It all depends somewhat on range of shot, wind factors or other noise, distraction level of the targeted deer, and how much preceved string noise the deer hears and how foreign that sound is preceived. My forty pound long bow shoots my hunting arrow 130 ftps. But im only shooting from one stand where the distance will be within 10 yrds. Tha bow makes hardly a wisper as the string is droped. I only shoot at deer that are relaxed and looking away. No dodging here!

      Reply
  2. Rudy L. says:

    I’m not saying I’m right, I’m not saying I’m wrong.

    My point ?

    You can use figure to represent any perspective you favor.

    You simply cannot state, “Fastest bow on the market, slowest deer on the planet”; then present middle of the road velocities to prove out your pre-selected hypothosis. It’s simply unscientific.

    There are crossbows today hitting 440 fps .
    Then,
    … you can never completely predict what a deer might do.

    Reply

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