FPS -> Joules for common bb weights

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FPS -> Joules for common bb weights

Postby Nocte » Thu Mar 29, 2007 1:23 pm

For those too lazy to use a calculator online, or if you're out at a game, I made up a chart for limits regarding muzzle velocity of our airsoft guns.

It might be a good idea to print or otherwise copy this information and keep it with your chronograph (if you have one). It may make chrono testing at events run more smoothly at events if the bolt action guys (or anyone not using .2g bbs, for that matter) to not have to switch out bbs.

For the sake of completion I listed weights that may not be used or recommended (like .12g bb weights).

OUTDOOR LIMITS:

AEG - 1.49J
bb mass____FPS
0.12g_______517
0.20g_______400
0.23g_______373
0.25g_______358
0.29g_______332
0.30g_______327
0.34g_______307
0.36g_______298
0.43g_______273


BOLT-ACTION - 2.81J
bb mass____FPS
0.12g_______710
0.20g_______550
0.23g_______513
0.25g_______492
0.29g_______457
0.30g_______449
0.34g_______422
0.36g_______410
0.43g_______375



INDOOR LIMITS:

ALL GUNS - 1.01J
bb mass____FPS
0.12g_______426
0.20g_______330
0.23g_______307
0.25g_______295
0.29g_______274
0.30g_______269
0.34g_______253
0.36g_______246
0.43g_______225
Last edited by Nocte on Fri Aug 17, 2007 4:05 pm, edited 2 times in total.
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Postby DMitri » Thu Mar 29, 2007 1:38 pm

Might as well add the formula...

v=√(2K/m)

v = Velocity (Meters/Second)
K = Kenetic Energy (Joules)
m = Mass (Kilograms)

You know, the whole, "Give a man a fish/Teach a man to fish" sort of thing...

The metric system makes it so difficult though. :cry:
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Postby Riddick » Thu Mar 29, 2007 1:49 pm

Nic, you should add the .43g bb to the bolt action section
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Postby PanzerFaust » Sun Apr 01, 2007 10:27 pm

http://www.1728.com/energy.htm

solves for energy mass or velocity, awesome little calculator
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Postby Sleepy » Tue Sep 11, 2007 12:35 am

Does this chart apply to the 8mm BBs as well? I'm not sure if the difference in surface area and density has an effect.
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Postby Nocte » Tue Sep 11, 2007 7:19 am

It applies, since the calculation only accounts for bb mass, not surface area or density. I believe most 8mm bbs are .34g, right?
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Postby TunnelRat » Tue Sep 11, 2007 8:18 am

8mms come in .27, .34 (most common), and .35 bio. What are your rulings on 8mm shotties (like the new US version M500)? Mine chronos at 330fps with .34g bbs, and it shoots 3 at a time. Now, it's not an AEG, but it's not a bolt action sniper rifle, either.
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Postby Nocte » Tue Sep 11, 2007 8:21 am

I would call that too hot, but its really a question for another thread.
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Postby Riddick » Tue Sep 11, 2007 9:04 pm

you should add .28g for aeg's
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Postby Big_Red » Tue Dec 25, 2007 11:09 am

.28 outdoor: 338.47 fps
Indoor: 278.66 fps.

That's a pretty sweet calculator, I didn't even bother using K=(1/2)mv^2.
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