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How To Make Your Own Nerf Chronograph


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#1 Garrett76z

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Posted 01 February 2007 - 04:38 PM

Well first let me say a couple things . . . virtually every other type of gun's output is measured in velocity of the projectile. If we can apply this to Nerf guns, then it becomes a much more exact science when modding guns.

Velocity of the dart should correlate directly to the distance the dart will go, but only if your darts go in a staight line. In other words, you could have a very high velocity dart coming out of the barrel but if it starts spiraling, fishtailing, etc it wont go very far. So you must have already found the correct weight,etc for your darts to go straight. Other than that . . . . . this method is fantastic for figuring out exactly what mods give you the most increase.

Everyone wants to know how far a gun will shoot. In the end this should be what matters when it comes to a guns power. However everyone always asks was it level? Angled? Wind? Skip? etc. etc." We want to eliminate as many variable as possible.

We want to measure VELOCITY of the darts. This is just like every other gun out there. Paintball, Airsoft, etc. They are all measured in feet per second (FPS)

I wanted to be able to tell without a doubt that one barrel length is better than another, or this type of stefan is better than another and so on. Wanna know EXACTLY how much faster your darts go without restrictors in it?

A chronograph is a device that measures velocity of a projectile, usually in Feet per Second. These arent cheap, usually around $50 cheapest and they dont even go low enough to measure a nerf gun. what to do . . .

Heres the basic idea:

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The tip of your barrel is placed exactly 10 feet from a piece of paper(suspended between two legs of a chair or whatever).

Use a audio splitter from your computer to two microphones, one place by your gun and one placed behind the piece of paper.

I used this model available from Target (and their website) for $9.99

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next download the free software called Audacity http://audacity.sourceforge.net/

This program will allow you to record sound and then go back and select specific points in time. With the chrono set up, hit record and fire your gun from exactly 10 feet away at the piece of paper. When you review what you recorded it should look something like this.

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Now select the very front/beginning of the first sound (gun firing) and drag it to the very front of the second sound(dart hitting paper). It should now tell you exactly how long it took for the dart to travel 10 feet, to the nearest .0001 second!

Do this 5 times for an average time and then go on to your next modification and see how much of a difference it made.

A typical totally stock gun will be in the .35 second range.

Now we want to convert that time into FPS (feet per second)

The formula is : 10 divided by your average time

For example: my bone stock Nitefinder had an average time of .3715 seconds. 10 divided by .3715 = 27fps(feet per second)


I tested this out all night on a Nightfinder and a Longshot. I cant believe how accurate and consistent this setup is. I recorded 5 shots each time and averaged them for each mod.


Very fun seeing the difference you make with mods, a stock NF shoots on average 27fps and mine right now is shooting at 101fps!

My highest average was a AT3k that went 140FPS, with individual shots as high as 160fps!

Here is a picture of the setup in my living room


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Edited by Garrett76z, 01 February 2007 - 04:45 PM.

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#2 nerfer34

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Posted 01 February 2007 - 05:13 PM

Are you Datsun at NHQ?
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#3 Rambo

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Posted 01 February 2007 - 05:15 PM

Wow. This is really nice, sadly, I don't think most people will go through all the setup...
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#4 NerfMonkey

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Posted 01 February 2007 - 05:51 PM

Are you Datsun at NHQ?


Datsun=Nissan

Garrett76Z

I assume so because of that.
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#5 KBarker

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Posted 01 February 2007 - 05:58 PM

This is a great idea! The two microphones ensures that both sounds are loud enough to be heard, very clever! This is a much better way to compare a gun's power than ranges, which are mostly subjective.
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#6 Garrett76z

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Posted 02 February 2007 - 12:30 AM

Yes, I post as Datsun on NHQ.

Really there is not too much to setup with this. 2 mics, 10 ft and a piece of paper.

As long as people are setting it up properly it should be somewhat easy to compare one persons findings to others.

Even if you only use it for your own comparisons its invaluable information for seeing what really works.
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#7 CaptainSlug

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Posted 02 February 2007 - 08:11 AM

Agreed. The lazy method I used to do a similar measurement is to shoot the darts at a hollow core door and measure the pitch and volume difference in the sound output between darts. But your setup provides for more consistency.
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#8 murakumo32

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Posted 02 February 2007 - 06:07 PM

Wasn't this exact same topic on the forums last year, with the exact same pictures?
Or was that just on HQ?
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#9 Garrett76z

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Posted 03 February 2007 - 01:54 AM

Wasn't this exact same topic on the forums last year, with the exact same pictures?
Or was that just on HQ?



Just HQ.
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