usable range of airsoft guns

[proffrink]

They use .20s because then they know the energy transmitted from the projectile. If people where permitted to use there own weight of bb for chrono test then they would need to work out the energy calculation for each possible weight.

If I used ur own ammo for the test it would be very easy to put .4+ in a mid cap. Shoot under 350fps then switch to .20/.25 when the game starts. This would potentially mean u put other players at risk especially if playing cqb where engagement distance are some time measured in inches.

.20 are used because this is the lowest weight most of us use so indicates the max velocity the weapon will shoot at.

I do think however that the hop units should be set to a minimum for the purpose of chrono test. I know what this would mean re setting it after but it's the only way to get a true reading. Especially if ur gun shoots at 349 fps.

Joule creep is a phenomenon caused my cronoing at .20 and capping the speed of the projectile rather than using the weight you would be for the game and calculating muzzle energy. They don't use .20s to crono with because it's accurate; they use it because it's quick and easy for people to understand (though if you ask me it actually confuses people more by making them inadvertently think they can use heavier weights to cheat the cronograph - see a inevitable thread that arises every month with someone asking if they can use .28s to bring their gun within site limits). If we had people cronoing their heaviest weight and getting the muzzle energy from that then even if they do switch to lighter BBs then the muzzle energy is never going to exceed what the crono'd with.

I don't quite understand what you're saying though as it seems you've got 'crono-cheating' with heavier weights and muzzle energy calculation muddled up. I won't go into it but Google it if you're unsure.

jcheese is right though. There's no easy solution beyond some sort of Joule chart and educating players. It's hard enough to get people to understand what '350fps' really means (i.e. a muzzle energy of around 1.15J) - let alone explaining Joule creep. Ultimately though there are people running around out there with sniper rifles firing the equivalent of 550fps because sites don't crono on the weight they'll be using - this is no fault of the player, but it is an issue. Not a big one, but it's there.

Really though we need a shift towards making people understand what muzzle energy is and throwing this fps nonsense out of the window. It's a tiny bit more of a strain on the beginner but it means readings will be far more accurate and everyone will pick it up in the same way they pick up how hop works. Like you say, jcheese, a chart like this attached to the crono is not a huge amount of effort.

 

[K@rl]

i would have thought that a .4 bb travelling at 350 fps has a higher muzzle energy than a .2 bb at 350fps.

There for by using a .4 for chrono @ 350 fps u would have a higher muzzle energy than a site with a limit of .2 @ 350 fps. And so "cheat" the chrono. This would then mean your gun was shooting hot when switching to .2 for in game action. I wasn't discussing the relation between speed mass and energy, merely people's desire to gain any "advantage" they can.

Please feel free to tell me if am wrong.

 

[proffrink]

You don't crono at 350fps - that's the point you're missing. You crono at 1.14J by calculating the muzzle energy from the speed and weight. 350fps with a .20g BB is around 1.14J. Want to use .30g? No problem, you use the chart and find what speed a .30g should be going if it's to have a muzzle energy of 1.14J; that's around 285fps (see below).

Edits for clarity (I hope)

Sniper rifle? Ok, if we crono 500fps on .20g we get 2.32J. Because of Joule creep, the liklihood that will stay at 2.32J when you switch to your .38g 'sniping BBs' is slim. You could now be shooting above 2.32J, and that's more than is allowed. This is because (and this is simplified to the max) air or propane or whatever propellant you're using has more time to transfer energy to the BB as it takes longer to travel down the barrel.

So what if we crono'd your gun with the .38g BBs you want to use? Well, we need to aim for 2.32J; about 360-365fps. Now you're going to always be shooting at 2.32J - no creep. If there's any creep at all from switching down on weights then it'll be negative, so you might end up shooting at 2.20J or less.

 

[K@rl]

u have just confirmed that I am right. Because a .4 @ 350 fps will be <1.14j it will infect be over 2j.

I never mentioned creep. Wasn't the basis of my point. By switching down a weight of being it will increase the fps. Because the energy transferred to the projectile from the piston will be the same.

 

[Snakeeyes75]

Well, I sem to have turned this thread in to a JC debate, sorry about that! One thing I have to add, a gun firing at say 550fps on .2's doesn't really gain any extra distance. 600 fps and you start seeing a bit of an increase. I've often wondered what the fps of a BB would be at 25 meter mark (In other words, how much force is lost in the first 20-25 meters). Having a 25/30 meter "ME" helps more than anything. Oh yeah, do people not realize that 1 yard is not the same as 1 meter? I now have a Hawke optics Laser range finder and even in the video review they talk about yards, it measures ONLY in Meters!

 

[K@rl]

My issue with hot guns isn't the increased distance it the risk to eye pro especially if it's a "reaction shot" at close range.

A .43 @ 350 fps = 2.45J. A .2 @ 2.45J will be travelling @ over 500 fps. The gun still transmits the same energy regardless of the weight. (Give or take)

 

[proffrink]

Well, I sem to have turned this thread in to a JC debate, sorry about that! One thing I have to add, a gun firing at say 550fps on .2's doesn't really gain any extra distance. 600 fps and you start seeing a bit of an increase. I've often wondered what the fps of a BB would be at 25 meter mark (In other words, how much force is lost in the first 20-25 meters). Having a 25/30 meter "ME" helps more than anything. Oh yeah, do people not realize that 1 yard is not the same as 1 meter? I now have a Hawke optics Laser range finder and even in the video review they talk about yards, it measures ONLY in Meters!

Sure, with a .20g it might not, but when you're shooting that same muzzle energy with heavier weights their energy degrades much slower. This is why a lot of people thing those using heavier weights are cheating because it carries that energy for longer and hits harder at longer ranges than a lighter BB that had the same energy leaving the barrel.

There are a few nuances here it would be unfair to ask people to understand, but one thing is for sure: Joule creep does exist and the current way of crono'ing doesn't allow for it. If I were shooting 400fps instead of 350fps would you be annoyed? I sure would.

My issue with hot guns isn't the increased distance it the risk to eye pro especially if it's a "reaction shot" at close range.

Any half-decent eye protection is rated much higher that anything we shoot at it, but fair point. Thing is, measuring muzzle energy rather than fps goes a way to mitigating hot guns better than anything we have now. There is the issue of energy conservation from heavier weights, but you're never going to solve that through any way other than banning heavy weights (which some CQB sites do).

Edit

This might help to understand why people use heavier weights of BB:

tl;dr, at 1.49J (still above site limits but just as an example figure), 0.43g BBs hold their energy for far longer than the rest so will go further. Ignore yellow as it's an 8mm BB so air resistance screws it over.

 

[Sacarathe]

.20 are used because this is the lowest weight most of us use so indicates the max power the weapon will shoot at.

I always assumed it's because of the neat convergence of 0.2 gram with 100m/s and 1 joule - over in metric land (Japan).

EDIT: So, it doesn't show replies while you're typing if you're on another page.

 

[K@rl]

Sure with a .20g it might not, but when you're shooting that same muzzle energy with heavier weights their energy degrades much slower. This is why a lot of people thing those using heavier weights are cheating because it carries that energy for longer and hits harder at longer ranges than a lighter BB that had the same energy leaving the barrel.

There are a few nuances here it would be unfair to ask people to understand, but one thing is for sure: Joule creep does exist and the current way of crono'ing doesn't allow for it. If I were shooting 400fps instead of 350fps would you be annoyed? I sure would.

Eye protection is rated much higher that anything we use, but fair point. Thing is, measuring muzzle energy rather than fps goes a way to mitigating hot guns better than anything we have now. There is the issue of energy conservation from heavier weights, but you're never going to solve that through any way other than banning heavy weights (which some CQB sites do).

Yes but muzzle energy is determined by the gun not the weight of bb. For every action there is an equil and opposit reaction. To bring it back to my point. Using a heavier Bb to get under 350fps means u have an increase energy. I know y people use them again not my point.

 

[proffrink]

You need to go back and read what I've typed as I think wires are significantly crossed here. You are not at all disagreeing with me - I am, as I said, not talking about 'crono cheating'. We are talking about how to stop Joule creep.

I'm also not sure where Newtons third law comes into this?

 

[Sacarathe]

Yes but muzzle energy is determined by the gun not the weight of bb.

But that was proffrink's point, the heavier BB is in the barrel longer.

Yes but muzzle energy is determined by the gun not the weight of bb. For every action there is an equil and opposit reaction. To bring it back to my point. Using a heavier Bb to get under 350fps means u have an increase energy.

I know y people use them again not my point.

Increase? No, not in the context of what you've said here.

More? Yes.

I suggest you stop saying FPS/Velocity and switch to "power" - makes things a lot less confusing And you don't have to use units.

 

[K@rl]

I know but I wasn't talking about that I was talking about cheats. And yes I ment more ?

However think my point is founded.

POWER ? Top gear style

 

[Dannn]

We're well off topic now but that's a player problem not a rules problem. Having a joule chart for all of the popular weights (or even ALL weights of BB) attached to the site chrono isn't a massive ask, if a player is thought to be attempting to cheat the system they could be asked to have ten of their BBs weighed before loading them into the magazine for chrono, although I agree that is a little heavy handed.

If someone wishes to cheat chrono, it's REALLY easy to do so.

You don't even need to use heavier ammo to cheat the crono... You can use .20's and still get way lower results if you know how to.If someone's adimant they want to cheat they can

 

[K@rl]

You don't even need to use heavier ammo to cheat the crono... You can use .20's and still get way lower results if you know how to.

If someone's adimant they want to cheat they can

Hop?

 

[proffrink]

I know but I wasn't talking about that I was talking about cheats. And yes I ment more

However think my point is founded.

POWER Top gear style

Hm, alright. This is GCSE-level physics though man - there are unfortunately no opinions.

You don't even need to use heavier ammo to cheat the crono... You can use .20's and still get way lower results if you know how to.

If someone's adimant they want to cheat they can

Beyond hop I don't see how you'd do this. Suppressor maybe as discussed in the other thread? This is less about purposeful cheating and more about unconscious Joule creep, but I think you got that

 

[K@rl]

Firstly I would like to make it clear I would never "cheat" the chrono. No need. It's rear for me to engage at over 30meters. Due to site.

However could somthin be added To the barrel/silencer to slow bb. Then removed.

 

[K@rl]

Also thank you proffink. Stopped me being board during xfactor. Lol

 

[Sacarathe]

Firstly I would like to make it clear I would never "cheat" the chrono. No need. It's rear for me to engage at over 30meters. Due to site.

However could somthin be added To the barrel/silencer to slow bb. Then removed.

Wouldnt worry about it, starting chrono is only a deterant to lazy cheats, kind of like how locking your house only stops the honest.

Its the spot chronograph checks which hold the real weight - of course they also don't matter without the baseline which the starting chrono provides.

 

[mimozine]

thank for the input guys, alot to digest.

another question you guys should be able to answer. now as i understand it snipers are alowed to be about 500fps max, and i think that is close to the actual legal limit from what i've read (2.5 joules of energy). now i was looking at a king arms blaser rifle, i like the look of it, they recon about 430-450 fps out of the box. so i was looking at upgrade springs etc available. a m170 spring was rated to 550fps and the m180 spring to 600fps. WTF? how is that? and how could i uprade a blaser to about the 500 mark?

 

[proffrink]

Short answer: Don't. Sniper rifles are made to certain tolerances and upgrading just one part of the whole propulsion system is going to have a knock-on effect. The sears and spring guide need upgrading too if you're putting a new spring in.

Really I'd say don't worry all that much. Your hop and barrel has far more to do with range (as discussed in this thread) with a stock gun than the speed at which it leaves the barrel. Get those right first and then work on upgrading your power source.

You'll get good range out of 450fps so long as everything is set up correctly.