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Re: FPS and Joule Converter

Posted: Fri Nov 26, 2010 8:58 am
by Pyrus_Conflagarus
Ok, maybe I should have been a little more specific. The debate itself hinged on whether muzzle velocity and/or range would be affected buy changes in air density due to altitude (this whole debate spring up due to a group whose usual venue is at about 9k ft going to OP Irene).  It was concluded that range would not be affected because yes, at lower altitudes you would have a higher air mass in the cylinder kicking out the BB, but the BB would then be traveling through higher density air and thus the air would attenuate the kinetic energy more.  However the muzzle velocity should be raised due to a higher mass of air being forced out (assuming the effect on the piston's compression rate is negligible).

Re: FPS and Joule Converter

Posted: Fri Nov 26, 2010 11:18 pm
by Doublewolf
I did doubt that the chronograph could accurately measure the actual energy of the bb. Now that it has been confirmed that that is not possible, what about a conversion chart? Most of us are honest people, and you already have to take people's word for the fact that they are using .2s anyway (unless bbs are provided, which they aren't always). It would be easier if everybody could chrono with the bbs they will be using on the field.

Re: FPS and Joule Converter

Posted: Fri Nov 26, 2010 11:46 pm
by Veimos
Doublewolf wrote: I did doubt that the chronograph could accurately measure the actual energy of the bb. Now that it has been confirmed that that is not possible, what about a conversion chart? Most of us are honest people, and you already have to take people's word for the fact that they are using .2s anyway (unless bbs are provided, which they aren't always). It would be easier if everybody could chrono with the bbs they will be using on the field.
Out of 4 sanctioned AOSC games that I have been to, only 1 has required me to have .20's loaded in my weapon.  Usually they just ask you what gram of bb you are using, and use the basic guideline I posted earlier.  So BASICALLY your idea is already in play, in an unofficial capacity.

Re: FPS and Joule Converter

Posted: Sat Nov 27, 2010 3:02 am
by D.Smitty
Doublewolf wrote: I did doubt that the chronograph could accurately measure the actual energy of the bb. Now that it has been confirmed that that is not possible, what about a conversion chart?
Already done.  It's a bit ghetto, as I did it in excel and just used the print screen key, but it functions just fine, I think.

http://www.southcarolinaairsoft.com/forums/http://www.southcarolinaairsoft.com/newforums/viewtopic.php?t=9

Re: FPS and Joule Converter

Posted: Tue Nov 30, 2010 6:53 pm
by Dominum
Doublewolf wrote: I did doubt that the chronograph could accurately measure the actual energy of the bb. Now that it has been confirmed that that is not possible, what about a conversion chart? Most of us are honest people, and you already have to take people's word for the fact that they are using .2s anyway (unless bbs are provided, which they aren't always). It would be easier if everybody could chrono with the bbs they will be using on the field.
This issue has already been remedied because the AOSC now provides mags and speedloaders with .20s in them for chrono at its events.

Re: FPS and Joule Converter

Posted: Wed Jun 13, 2012 9:19 am
by slimshady222
can chrono's mesure in joule's

Re: FPS and Joule Converter

Posted: Wed Jun 13, 2012 2:57 pm
by SteevoLS
It's not really possible to measure joules based on FPS alone. A few chronos will calculate it if you tell it what weight your BBs are but it is only accurate as long as you input the correct weight.

Re: FPS and Joule Converter

Posted: Wed Jun 13, 2012 7:19 pm
by slimshady222
cause in france minors cant have guns above .08 joules but I highly doubt that they even listen to those rules.

Re: FPS and Joule Converter

Posted: Wed Jun 13, 2012 7:51 pm
by SteevoLS
Those are actual laws, not organization-specific rules like the AOSC sets forth. It would be considered a criminal offense to A. sell you a gun over .8j, or B. use a gun over .8j as a minor.

Re: FPS and Joule Converter

Posted: Wed Jun 13, 2012 8:59 pm
by jsts ghost
Slim, you will find that the french has zero excuse for Americans. You must follow all there rules. So make sure that you read up on them. G.I. Joe plug, Knowing is half the battle! Using the knewledge is the other half.

The only way to be 100% about measurment of joule is to have an impact measuring. As the ones that have studied it has told you, chronos only give a programmed mesurement of speed times mass divided by distance. A bb does not acheve (sp) max speed until 1 inch out of the inner barrel. And Joule is maxed at the inner barrel opening. So no, our handheld chronos gives an educated guess.

Re: FPS and Joule Converter

Posted: Thu Jun 14, 2012 8:15 pm
by slimshady222
I dont think they really follow those rules there though because we had a friend over from france and he said the cops dont really care that much about those litttle ofenses as much as like stealing. He said that if cops drive past minors drinking they dont even stop to tell them to stop. Same goes with smoking

Re: FPS and Joule Converter

Posted: Thu Jun 14, 2012 8:25 pm
by jsts ghost
Well there are two types of people; those that care about law and order and those that don't. The latter need not be around me.

Re: FPS and Joule Converter

Posted: Thu Jun 14, 2012 8:39 pm
by PRincess
jsts ghost wrote:Well there are two types of people; those that care about law and order and those that don't. The latter need not be around me.
Amen to that! Go ahead and break the law, but don't come crying back to us when you get in serious trouble.

Re: FPS and Joule Converter

Posted: Fri Jun 15, 2012 8:53 am
by Star_folder
hmmmmm, I'm thinking stuff has changed since you've talked to your friend. It's likely you won't be able to bring your airsoft guns into France. Cybergun has pulled a rather crappy stunt by copy writing anything and everything airsoft. And by that I mean they have the terms Hop-Up, AEG, Airsoft, etc. You can't buy, or own, anything airsoft gun that doesn't have cybergun tattooed on the side of the gun.

You might want to double check on that, but from what I understand, you'll not be able to bring your guns into the country if they see them. There've been a whole bunch of articles to show up lately about French Airsofters trying to fight Cybergun for what they have done.

Re: FPS and Joule Converter

Posted: Fri Jun 15, 2012 2:06 pm
by atl
This is what I found on Wikipedia and a few other sites while looking around
Visible transportation of replica firearms in public areas is forbidden. They must be covered with something, for example, a firearm case. Land owner's permission is needed to play airsoft in any area.
Minors (under 18) can only buy airsoft guns which are under 0.08 joules in power. Minors can not use guns over these 0.08J. Airsoft guns may only have a power under two joules (450 fps whis 0,2g bb's), otherwise they are no more qualified as airsoft replicas but firearms and owners should follow the French weapons law (dated 1995).