FPS ou JOULES

[Ronan]

Originally Posted by Greylocks

I dont know... we learned english to understand you, can you not learn french? There is no forum request that states everything here should be translated.
And translating Quebecois is not immediately obvious.

(I am not going to retract what I said, but I will say I'm sorry. Why did I say it? Because for YEARS myself and anyone else who happens to not be english has been told, even ordered, to learn the 'other' official language of this country to even be accepted into it. And then I see comments like that which just push the wrong buttons. We ALL have the Right to express ourselves in our own language and it is up to us to figure out what is written. We francophones dont ask for every english post, no matter how useful, to be translated for us. Same should be done in return. So I am sorry you did not have the chance, or the time, to learn my language. I hope you do someday.)

It's a lot easier to learn English than to learn French. I wouldn't blame him if he wouldn't even want to try

P.S: I speak and write broth in French and English fluently.

[Jimski]

cinetic energy = 1/2 [Mass X (SpeedxSpeed)]

so bb's weight change the resulting energy, and speed changes it too.
since Speed is elevated to a square, it's the parameter that changes the most the resulting energy.

[Greylocks]

Originally Posted by Ronan

It's a lot easier to learn English than to learn French. I wouldn't blame him if he wouldn't even want to try

P.S: I speak and write broth in French and English fluently.

So do I, obviously. But I will stand by my comments. It's not just about him, really, but everyone else who asks. Every language is hard to learn, in one way or another.

[Greylocks]

Simply put. A fast light BB will produce the same impact as a slow heavyer BB. But a gun that shoots a .20 gram BB at, say 380fps will probably shoot a .25 at around 360 or maybe even 340. The end result is (for our purpose) the same.

This is ballistics 101.

[Sterling]

Ha! Knowing French does help!

FPS is a speed. Joules (If I remember what we talked about in Physics last year and correct me if I am wrong) is an amount of energy*release.

[FOX_111]

Originally Posted by Greylocks

Si le test est fait avec .20 et la personne prends du .25 ou plus pesant, la velocite de la bille diminue. Donc la force de frappe ne change pas vraiment.

Le probleme, c'est quand quelqu'un veut tricher au chroni et met des balles plus lourdes pour passer Ã* la barre du 400fps.

Les regles de fps max sont basé sur une mesure prise avec du .20g. 400fps avec du .25g ou du .30g c'est pas vraiment la même force de frappe...

Je suis normalement plus diligent pour les snipers BA, puisqu'une seul balle est moin domageable qu'une rafale de 15-20 balles. Pour les AEGS, aux milsims que j'organise, je les mesure avec mes .20g ou au moins, je demande Ã* la personne qu'elle poid de balle est Ã*. Dans le doute, on met mes balles.

[Ronan]

Originally Posted by Greylocks

So do I, obviously. But I will stand by my comments. It's not just about him, really, but everyone else who asks. Every language is hard to learn, in one way or another.

Well if he doesn't know X language, someone will translate it for him.

[Drake]

Originally Posted by Sterling

Ha! Knowing French does help!

FPS is a speed. Joules (If I remember what we talked about in Physics last year and correct me if I am wrong) is an amount of energy*release.

That's correct, FPS is speed and Joules are energy.

In this case you can determine energy with:

(Mv² * W) / 450100


It's the standard equation for kenetic energy of motion: Speed in FPS (in this case Muzzle Velocity) squared, multiplied by the projectile's weight in Grains (1 gram == 15.432 grain). In this case we're also incorporating gravity (for simplicity's sake, we pre-calculate gravity as a constant*). The actual for formula is

(Mv² * W) / 2 G


The result will be in imperial Foot-Pounds (ft-lbs.) since we used imperial units to begin (namely FPS).

You can convert ft-lbs to Joules by multiplying by 1.356 (i.e., 1 ft-lbs. == 1.356 J.)




* gravity is generally accepted to be 980 cm/sec² on Earth. Since we're using FPS we have to convert that, which becomes 32.15 ft/sec². Similarly, we're using Grains rather than Pounds to calculate ft-lbs.: 437.5 grains == 1 ounce, 16 ounces == 1 pound (lbs). So:

( 437.5 * 16 ) * ( 2 * 32.15 ) == 450100

[leblanc74]

Originally Posted by flame

I'll give you 20% discount on your next order Mike.

....I feel special

[Greylocks]

Originally Posted by FOX_111

Le probleme, c'est quand quelqu'un veut tricher au chroni et met des balles plus lourdes pour passer Ã* la barre du 400fps.

Les regles de fps max sont basé sur une mesure prise avec du .20g. 400fps avec du .25g ou du .30g c'est pas vraiment la même force de frappe...

Je suis normalement plus diligent pour les snipers BA, puisqu'une seul balle est moin domageable qu'une rafale de 15-20 balles. Pour les AEGS, aux milsims que j'organise, je les mesure avec mes .20g ou au moins, je demande Ã* la personne qu'elle poid de balle est Ã*. Dans le doute, on met mes balles.

Il y aura toujours des tricheurs, c'est pourquoi les tests sont normalement faits par une personne avec les memes billes (ce que tu fait). Les tricheurs se font generalement prendre eventuellement, et se ramassent tout seuls.

[ILLusion]

Originally Posted by Greylocks

Simply put. A fast light BB will produce the same impact as a slow heavyer BB. But a gun that shoots a .20 gram BB at, say 380fps will probably shoot a .25 at around 360 or maybe even 340. The end result is (for our purpose) the same.

This is ballistics 101.

I've made a pretty detailed post about this topic before, but to sum it up:

What you've said is true... at the muzzle.

At 100 feet, anyone can attest that a 0.25g BB will hit harder than a 0.20g BB. Why? Because it retains much more energy over the flight path.

The main issue, however, is when gas guns are involved, because their output is not linear. Heavier BBs shot out of a gas gun will output MORE energy than a lighter BB will. In some cases, a gas gun that shoots a 0.20g BB at 330fps can output a 0.25g BB ALSO at 330fps. This is where the danger lies, and why the debate is open on why games should be limited by JOULES, rather than by velocity.

At least when limited by Joules, the gun can be tested with whatever weight BB the gun will be fielded with, as long as the user is honest enough to state that intent and the resources are available to make the appropriate calculations/conversions.

[Greylocks]

I know, that's why I keep my answers as short as possible. The rest is written down.

[FOX_111]

We should have a new way to "chroni" gun. Like shooting on a flat surface that mesure the joule output on impact.

No mather what type of BBs used, that test would be very fast and precise. Place the musle on a certain line, fire at the target and the result is shown on a small LCD in joules.

I wish we had that, it would make chroniing a joy.

[Drake]

Shoot into a bowl of Jell-O... like ballistic gel for airsoft. Then we can eat the test material. Everyone wins.

[krazie Sj]

And some asshat will choke on the BB that's stuck in there.