Fps vs joules and the law

[Niktimes3]

Hi all I recently played a game at a different site from my normal one. all my guns were firing way under the FPS. but now I’ve been told that they were all too hot due to the joules. At that site the max J for a rif that has full auto is 1.14J ( uk law is 1.3) The site told me this is due to their insurance. but in the five years I’ve been playing Airsoft I never have been to a site that request you to measure in Joules. The law came out in 2017 and has taken them till 2021 to enforce it on this site. so my question is how does everyone feel about this and is everyone finding this problem across the UK?

https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/610380/2017_04_19_-_PCA2017_firearms_provisions_-_HO_Circular_-_final.pdf

 

[Nick G]

Our local site tests Joules using your own BBs . Seems sensible to me , while joule creep isn't too much of an issue with AEGs it very much is with snipers and GBBRs  . 1.13 j seems to be a relativly standard level for most sites since it equates to the usual 350 fps on .20s .

I think more sites are becoming aware of the issues surrounding heavy BBs in some platforms now and are quite rightly measuring joules to make sure that they and you are complying with the law, by setting a limit below 1.3 j they are alowing some headroom  for both.

Will people still try to cheat chrono ? yes , some people will but it is a better way to check outputs.

 

[EDcase]

My two sites still use fps but test with your chosen BB weight.  It would be very easy for someone to lie about their BB weight though.

 

[Rogerborg]

all my guns were firing way under the FPS. but now I’ve been told that they were all too hot due to the joules.

Reality is a harsh mistress.

The only "problem" here is that there are still sites out there who are chronoing like it's 1999.

Can you please tell us which sites didn't spot that your toys were shooting hot, so that I can make a note to avoid them?

 

[Adolf Hamster]

Hi all I recently played a game at a different site from my normal one. all my guns were firing way under the FPS. 

you know fps is a measurement of velocity not energy right?

when we use the term fps in airsoft what's actually meant is fps on a 0.2g bb and that latter part is what makes it a convoluted way of stating energy, who's SI unit is joules......

the reason velocity is the thing people use is because that's what chronographs measure/display, and the reason it's feet per second rather than metres per second is the same (read: dumb) reasons we buy petrol in litres, milk in pints, sugar in kilos and steak in oz because the uk is stuck in measurement system purgatory.

 

[Niktimes3]

you know fps is a measurement of velocity not energy right?

when we use the term fps in airsoft what's actually meant is fps on a 0.2g bb and that latter part is what makes it a convoluted way of stating energy, who's SI unit is joules......

the reason velocity is the thing people use is because that's what chronographs measure/display, and the reason it's feet per second rather than metres per second is the same (read: dumb) reasons we buy petrol in litres, milk in pints, sugar in kilos and steak in oz because the uk is stuck in measurement system purgatory.

I completely understand what you’re saying but that wasn’t my question my question is why has it taking Site so long as the law came out in 2017 also if you google airsoft sites around Hampshire you’ll notice that only one is testing in J everyone else is still using FPS with a 0.2

Reality is a harsh mistress.

The only "problem" here is that there are still sites out there who are chronoing like it's 1999.

Can you please tell us which sites didn't spot that your toys were shooting hot, so that I can make a note to avoid them?

Better than that I can tell you that every site around Hampshire other than one measures in FPS if you’re looking to avoid anywhere that measures FPS around here you’ll need to go to ambush Airsoft

 

[Adolf Hamster]

I completely understand what you’re saying but that wasn’t my question my question is why has it taking Site so long as the law came out in 2017 also if you google airsoft sites around Hampshire you’ll notice that only one is testing in J everyone else is still using FPS with a 0.2

that was my point, fps on 0.2j is a joule measurement, just in confusing units that make it seem like it isn't.

the reason it's taken so long is because there's not much agreement in chrono standards, for example hop on or off, player weight or site weight, quote limits in fps or j, and sites generally can't be bothered putting too much effort into it, much easier to just remember a number.

i've lost count of the number of times i've had to explain that no, my gun is not shooting low, it's heavy ammo, especially when they've set the weight on the chrono and are reading the fps figure (which is always a raw figure of the velocity measurement) rather than the calculated joule figure.

 

[Niktimes3]

Reality is a harsh mistress.

The only "problem" here is that there are still sites out there who are chronoing like it's 1999.

Can you please tell us which sites didn't spot that your toys were shooting hot, so that I can make a note to avoid them?

You wouldn’t like playing here if your worried about 1.40j on a dmr

https://www.worthingairsoft.co.uk/rules_safety.php
It’s 1.64j and no fps limit 

 

[Rogerborg]

You wouldn’t like playing here if your worried about 1.40j on a dmr

Unlikely, since I run a 1.8J DMR myself.

What I'm more concerned about are people taking point blank shots with guns over (potentially way over) 1.3J because they've got it in their heads that "under 350fps" means that it's fine whether they're shooting 0.2g or 0.48g.

It’s 1.64j and no fps limit 

Good. The sooner sites stop thinking and talking in term of fps, the sooner we can put this all behind us.

All airsoft chronos show a Joules value. You don't need to work anything out, you just set your BB weight and look at that number.

For example, I can tell you that my new TAC-41 boltie shoots at 1.8J with 0.43g BBs with the stock spring, and 2.27J with 0.43g with a 100N spring (minus 4 coils).  I didn't even look at the fps value, and nor could I tell you what it might shoot at with 0.2g because it'll never, ever have anything that light in it.

It's time to move on from 0.2g and fps.  Join us in the future, we have flying cars and rocket boots and all sorts.

 

[Adolf Hamster]

Join us in the future, we have flying cars and rocket boots and all sorts

Really!? I hope your joking because otherwise imma feel cheated.....

 

[Cannonfodder]

My regular site, along with the majority of other sites I've visited recently, all chrono with fps but change the limit depending on the bb weight used

 

[Rogerborg]

My regular site, along with the majority of other sites I've visited recently, all chrono with fps but change the limit depending on the bb weight used

Er, well, yes. They're chronoing in Joules, but living in denial.

There's a practical argument about it being slightly quicker, maybe, to cross reference an fps number on a chart than to change the setting on the chrono, especially if someone is using an unusual weight.

My main issue is with still thinking and talking in terms of 0.2g and 350fps as a default, which is now an edge case for woodland.

Thinking about it, the one weight that you probably don't need on a chrono for woodland is 0.2g.  Really, how many people are still shooting that?

 

[The Waco Kid]

Well I do…. I just fire a lot of it. ?

 

[Tommikka]

Unlikely, since I run a 1.8J DMR myself.

What I'm more concerned about are people taking point blank shots with guns over (potentially way over) 1.3J because they've got it in their heads that "under 350fps" means that it's fine whether they're shooting 0.2g or 0.48g.

Good. The sooner sites stop thinking and talking in term of fps, the sooner we can put this all behind us.

All airsoft chronos show a Joules value. You don't need to work anything out, you just set your BB weight and look at that number.

For example, I can tell you that my new TAC-41 boltie shoots at 1.8J with 0.43g BBs with the stock spring, and 2.27J with 0.43g with a 100N spring (minus 4 coils).  I didn't even look at the fps value, and nor could I tell you what it might shoot at with 0.2g because it'll never, ever have anything that light in it.

It's time to move on from 0.2g and fps.  Join us in the future, we have flying cars and rocket boots and all sorts.

Really!? I hope your joking because otherwise imma feel cheated.....

The future is in the past, they weren’t all they were cracked up to be

View attachment 88746

Spring powered boots worked out better than ‘rocket’ pistons

 

[Cannonfodder]

There's a practical argument about it being slightly quicker, maybe, to cross reference an fps number on a chart than to change the setting on the chrono, especially if someone is using an unusual weight.

Exactly this. It may only be a few seconds each time, but when you've got busy site these few seconds all add up quickly

 

[Rogerborg]

Exactly this. It may only be a few seconds each time, but when you've got busy site these few seconds all add up quickly

Maybe.  But is it quicker to press a button two or three times than to look at a number, than to look at a different number, then do the finger-shuffle on a spreadsheet to find the first number?

If I'd ever seen a site that had printed out just the limits for each BB weight and gun type, it would make more sense, but I've yet to see that. It's either a generic chart where they're looking up a Joules number anyway, or worse, the marshal's got something on his phone to work it out which is almost certainly slower than changing the chrono setting.

Could be wrong, but it's marginal either way.

 

[MadMole]

Thats exactly what every site I've ever played at has,  A sheet with the maximum FPS allowed for each BB weight, often stuck on the chrono. You just step up, tell em your BB weight and shoot, FPS comes up, if its over for your weight then hot gun. 

Does rely on folks honestly stating BB weight, but if folks are not honest enough to say the correct weight they are also naughty enough to turn the hop up a ton to slow the BB or off to allow gas escape or some other way of altering speed.

The truth is Joules is an indirect measurement and in reality it is FPS that is measured directly. and unless you start weighing BB's or providing test BB's and then watch RIF being fired at a distant target to check Hop is set etc you are always doing test on trust. Would be nice if sites had the time to do it all properly. And then we have the whole issue of HPA!!! and what gas was used on a refill for GBB's

 

[Rogerborg]

 in reality it is FPS that is measured directly

If we're going to be technically correct - the best kind of correct - chronos only measure elapsed time, then calculate fps from that.  Joules is just another step down the line.  Let the silicon take the strain.

A sheet with the maximum FPS allowed for each BB weight, often stuck on the chrono.

It seems obvious, but I've yet to see it up here.

Hmm, I might start laminating them and sticking them up at chrono stations, like some sort of efficiency vigilante.

 

[Monkeywrencher]

Finally, the Hero we deserve...

 

[Cannonfodder]

providing test BB's and then watch RIF being fired at a distant target

IIRC this is what they did at Urban Assault