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-   -   Joules vs fps (https://www.airsoftsniperforum.com/showthread.php?t=62079)

Sniperfitter 01-06-2020 01:33 PM

Joules vs fps
 
My local field has had a 500 fps limit on snipers for as long as they've been open and they're switching to joules. They're saying 2.26 joules for sniper rifles with a .20 and the owner said that's equal to 500 fps... why "change to joules" if that 2.26 is equal to 500 fps? Is there something I dont know?

Blind Sniper 01-06-2020 01:37 PM

Do they put bbs in your gun to chrono? Or do they chrono with what you shoot? Chronoing in joules avoids joule creep or people lying about bb weights. That 2.26 might be overall. So even with a .48 your limit is 2.26.

MagicMarker 01-06-2020 01:54 PM

Energy is calculated based on speed and weight. Energy describes the power output of a rifle- BB speed is insufficient. Regulating power using only BB speed is completely nonsensical- getting hit by a .2g BB at 500FPS will hurt, but getting hit by a bowling ball at 500FPS will turn you into pink mist. While BBs don't get as heavy as bowling balls, the difference between a .2g BB and a .4g BB is far from negligible.

There's no perfect solution to guarantee everyone on the field is playing at the desired power levels, so the conversation of how to best regulate players' power outputs can get pretty complicated, but simply measuring in joules is usually just as easy as measuring in FPS, and already does an infinitely better job at mitigating power level variation between players due to BB weight.

Again, I want to reiterate how it is quite literally just wrong to attempt to regulate power while only measuring BB speed. If a field does this, you should be very cautious, as it is truly unsafe. Measuring BB speed only, someone could reach as high as 8 joules with your field as example (.69g at 500FPS)- entire countries often limit to 1 joule, and the highest I've seen in the US was 3.5 joules...

Jsmithski 01-06-2020 02:03 PM

They will most likely chrono you with your bbs, not 0.2 (otherwise it makes no sense). If your rifle has a joule creep it will shoot hotter with heavy bbs than it would result from simple FPS/weight calculation.

bbbear 01-06-2020 05:46 PM

Quote:

Originally Posted by MagicMarker (Post 413959)
getting hit by a .2g BB at 500FPS will hurt, but getting hit by a bowling ball at 500FPS will turn you into pink mist

According to https://www.calculatorsoup.com/calcu...cs/kinetic.php, a 16 pound bowling ball travelling at 500 FPS = 84,280.2 J.

Quote:

Originally Posted by MagicMarker (Post 413959)
There's no perfect solution to guarantee everyone on the field is playing at the desired power levels, so the conversation of how to best regulate players' power outputs can get pretty complicated, but simply measuring in joules is usually just as easy as measuring in FPS, and already does an infinitely better job at mitigating power level variation between players due to BB weight.

Again, I want to reiterate how it is quite literally just wrong to attempt to regulate power while only measuring BB speed. If a field does this, you should be very cautious, as it is truly unsafe. Measuring BB speed only, someone could reach as high as 8 joules with your field as example (.69g at 500FPS)- entire countries often limit to 1 joule, and the highest I've seen in the US was 3.5 joules...

I agree.. FPS is a completely illogical means to measure the output of an airsoft gun. I wish gun FPS was advertised instead as KE. Sure, everyone probably can remember that 400 FPS with .20g BBs is about 1.5j, but still. My field (and other NEASG fields) allow up to 1.858j from AEGS and 3.51j BASR (with 100' MED). So I know 450 FPS and 570 FPS (or so) would be under the max joules, respectively.

It's still a pain in the ass to look up. lol

MagicMarker 01-06-2020 07:17 PM

Quote:

Originally Posted by bbbear (Post 413977)
According to https://www.calculatorsoup.com/calcu...cs/kinetic.php, a 16 pound bowling ball travelling at 500 FPS = 84,280.2 J.

Lol, quick Google says that's about four times the energy of a .50 BMG? :P


Quote:

Originally Posted by bbbear (Post 413977)
It's still a pain in the ass to look up. lol

Well it can be - I know firsthand, my chrono doesn't calculate joules - but most chronos used for airsoft do calculate for you, so usually it's not actually more work for field admins checking players.

bbbear 01-06-2020 07:27 PM

Fun with chronos!

I have some .12s for some reason.. put one through my VSR for S&G.. then in contrast, one of my usual .45s.
https://i.imgur.com/QSSSttR.jpg

When I switched the chrono to .45 weight, it didn't clear the previous entry, and gave me some otherworldy joules. lol
https://i.imgur.com/EZzyrtJ.jpg

(Using the ACETECH AC5000 chrono. $55 at Amazon.)

Sniperfitter 01-06-2020 09:45 PM

Where tf can you use 630 fps?! Lol

Sniperfitter 01-06-2020 09:46 PM

Bruh a .45 ain't much faster lmao

bbbear 01-07-2020 05:26 AM

Quote:

Originally Posted by Sniperfitter (Post 413987)
Where tf can you use 630 fps?! Lol

Pretty much anywhere in the Northeast US.

So long as the kinetic energy doesn't exceed 3.51j.

Jsmithski 01-07-2020 08:41 AM

Quote:

Originally Posted by Sniperfitter (Post 413987)
Where tf can you use 630 fps?! Lol

600-650 [email protected] is normal for sniper rifles in Poland. DMRs are 500-600 depending on the field. Assault up to 450 (full auto with 30m MED). CQB 300 full auto, 350 single no MED.

Sniperfitter 01-07-2020 01:06 PM

Damn I didn't know that lol

Pu7z 01-07-2020 01:37 PM

Quote:

Originally Posted by Jsmithski (Post 414005)
600-650 [email protected] is normal for sniper rifles in Poland. DMRs are 500-600 depending on the field. Assault up to 450 (full auto with 30m MED). CQB 300 full auto, 350 single no MED.

Jeez, I can just imagine the amount of joule creep going around...

What are the MEDs for snipers and DMRs?

Jsmithski 01-07-2020 01:54 PM

Quote:

Originally Posted by Pu7z (Post 414017)
Quote:

Originally Posted by Jsmithski (Post 414005)
600-650 [email protected] is normal for sniper rifles in Poland. DMRs are 500-600 depending on the field. Assault up to 450 (full auto with 30m MED). CQB 300 full auto, 350 single no MED.

Jeez, I can just imagine the amount of joule creep going around...

What are the MEDs for snipers and DMRs?

30m. Here’s the most common rule set
https://asgard.events/web/regulamin_...e_Rules_EN.pdf

Pu7z 01-07-2020 02:31 PM

Quote:

Originally Posted by Jsmithski (Post 414025)
30m. Here’s the most common rule set
https://asgard.events/web/regulamin_...e_Rules_EN.pdf

Yeaaah, that hurts hahaha.

I try to keep a self imposed MED of 50m when using my sniper at 3 - 3.5J, below that there's a risk of rupturing the skin.

I once shot a guy by accident at 20m, he did not like that. I was aiming for another guy at about 70m in a corridor of buildings, and the lucky subject passed running after the bb was already in the air. Got it to the side of the head, between the eye and the ear, no protection. It bled, of course.

Never had the chance to apologize to the guy, and felt bad for it.


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