FPS limits and BB weights

[MUCKYMICK]

Re: FPS limits and BB weights

no it will never happen that way,once the bb start's moving it is subject to the force that is moving it ,the gas will expand at a set rate and eventualy fill the barrel forcing the bb from the barrel

[thekonassure]

Re: FPS limits and BB weights

once it starts moving it takes more energy hence more air to start moving a heavier bb

[MUCKYMICK]

Re: FPS limits and BB weights

no it take's a small amount of force to overcome the weight of the bb once it has started to move the bb the gas will expand at a set rate pushing the bb to the terminal vilocity that can be achived with the volume of gas that it takes to fill the barrel and expell the bb from it,any extra volume of gas is wasted.

[thekonassure]

Re: FPS limits and BB weights

The weight of a .20 bb yes but what about a 1g bb or even heavier then that ? Hmmm not that Id want to fire anything over 1g out of my gun lol

Your point holds merit and you seam to be right but I still want to do some practical testing. Any reason to shoot a gun lol

[Planemo]

Re: FPS limits and BB weights

I was under the impression that gas stored under pressure would revert back to a liquid state?

Apply enough pressure and yes, it does. AFAIK all airsoft gas guns store propane as a liquid. I was only suggesting that when you pull the trigger, maybe the GBB mags siphon gas from the top of the mag, not the liquid from the bottom.

If this is the case, it matters not a jot that propane (gas) is being used rather than the air around us (as in an AEG), as propane gas doesn't expand any more than air does.

If a like for like gas gun is sending a BB at a higher velocity than an AEG then it is indeed either sending liquid propane into the barrel OR its simply a difference in the mechanics of the gun, ie the proportion of gas entering the barrel is more than the air volume in the AEG.

Whether one uses propane gas or common or garden air shouldn't make any difference to velocity is the point I was trying to make, badly it seems

[TS_Welshy]

Re: FPS limits and BB weights

I have 2 things to say...

1:

I think it needs to be in simple terms, I know its probably not the best way to word it but....

Using a weight heavier than .2 makes the gun more powerful, so even if its travelling slower (FPS) its hitting harder (JOULES) .

Please revise Physics.

2: WHY are we having this discussion??? Can't we all just stick a few 0.2s at the top of our mags for the site chrono check, make sure it's safe and then play the game? If the gun is hot the gun is hot, you can't use it. All this talk of cylinder volume and gas expansion is a lot of pointless rubbish. What matters is the chrono result and that's it. Whatever causes the chrono result to be above 350 doesn't matter, if it's hot you can't use it. Use a different gun, chrono with 0.2s like everybody else and if it's safe, use it. If you build all your guns to run around 310fps instead of trying to max site limits (assuming 350) then no variable is likely to ever add the extreme 40fps extra to make the gun hot. Done.

Chronoing with different weight bbs and doing the maths would be fine in an ideal world where everyone is honest. It would never be an exact calculation but the variables wouldn't be enough to make the guns much more dangerous. But you will get cheaters who say they are using 0.2s when they are using 0.25s, and people (like above) who don't have a proper understanding of the Physics of it and won't be happy about people chronoing with 0.25s because they think it's more dangerous or whatever. Just use 0.2s?

[thekonassure]

Re: FPS limits and BB weights

I have 2 things to say...

1:



Please revise Physics.

2: WHY are we having this discussion??? Can't we all just stick a few 0.2s at the top of our mags for the site chrono check, make sure it's safe and then play the game? If the gun is hot the gun is hot, you can't use it. All this talk of cylinder volume and gas expansion is a lot of pointless rubbish. What matters is the chrono result and that's it. Whatever causes the chrono result to be above 350 doesn't matter, if it's hot you can't use it. Use a different gun, chrono with 0.2s like everybody else and if it's safe, use it. If you build all your guns to run around 310fps instead of trying to max site limits (assuming 350) then no variable is likely to ever add the extreme 40fps extra to make the gun hot. Done.

Chronoing with different weight bbs and doing the maths would be fine in an ideal world where everyone is honest. It would never be an exact calculation but the variables wouldn't be enough to make the guns much more dangerous. But you will get cheaters who say they are using 0.2s when they are using 0.25s, and people (like above) who don't have a proper understanding of the Physics of it and won't be happy about people chronoing with 0.25s because they think it's more dangerous or whatever. Just use 0.2s?

Because the theory is that with a heavier bb in the correct gun you could get a lot more power I`d guess it would be no more then 10% but other people seam to be acting like it would be anything from 20% to 50%

Even if it was just 10% and the main gun it effects is long barrel gas guns so snipers.

Assume a 500fps sniper limit guy chrono`s with .20`s then pops in .30`s or .40`s and gets an extra 10% ? thats 50fps more if it was on a .20 that`s a lot more power I mean add 50fps to most peoples aegs and there gun becomes too hot to play with.

So I think maybe we should just say that all guns are chrono`d with .20`s except long barrel snipers that are to be chrono`d with .30`s and set the correct fps limit.

Maybe even say 350fps for normal guns on .20`s and 350fps for snipers on .30`s and a min engagement range of 30m`s for snipers ?

[MUCKYMICK]

Re: FPS limits and BB weights

The reason most site allow sniper single shot weapon's to shoot at a higher fps than aeg's is because they are allowed to and they are generaly fired a distance so the bb will have lost some of it's energy by the time it arrive's at the target.
different fps rule's apply to different form's of airsoft weapon's you are looking from the point of an aeg and applying those fps /impact force rules to single action weapon's ,it does not matter what you think/understand if a site say's the fps limit for a type of weapon is set at x fps and you need to use a.2 bb to test that fps then that is what should be used as that site will know what impact force the .2 bb will have and every other weight of bb shot from that weapon will have .
Like i have already said any body not using a .2 bb or declaring they are not using a .2 bb when being chronoed should be kicked in the nut's for trying to do so as they are clearly trying to sneak a hot gun past the chrono.
The bottom line is if site tell's you to chrono with .2 bb and not exceed a set fps then that is what must happen end of.

[private parts]

Re: FPS limits and BB weights

I think people are on about gas sniper rifles now, saying you could be 500fps on .2s, but 502 fps on .25s, bad example i know but basically saying the .25 will be in the gas barrel longer as travelling slower but more time to accelerate.

[MUCKYMICK]

Re: FPS limits and BB weights

No it does not work like that ,the bb cannot take longer to leave the barrel and be traveling faster ,if the fps increases the time the bb spend's in the barrel decreases as it's traveling faster .
If a .2 bb leave's a barrel at 500fps then any heavier bb that is fired from that weapon will travel slower less fps but will have a slightly increased impact force as the bb has more mass ,this is allowed for single shot weapon's.
The only thing that increase's the fps on gas gun's is the barrel length if you make it longer than it normaly would be (fit a longer barrel or silencer with a barrel extension)then the bb will be in the barrel loner and have more time to be accelorated,the heavier a bb the more force it required to move so the same amount of gas that would move a .2 bb at 500fps will not move a .3 bb faster it will only move it slower as more energy is spent moving it.
Please stop just use a.2 bb to chrono any gun when you are asked to do so.

[North West Outpost]

Re: FPS limits and BB weights

Hold the bus....I just had a thought....

It is simple isn't it. Site rules with snipers say 500fps with a 0.2. (or what ever)

That's it then. That's all we need to worry ourselves with surely.

[ElCarl]

Re: FPS limits and BB weights

I think people are on about gas sniper rifles now, saying you could be 500fps on .2s, but 502 fps on .25s, bad example i know but basically saying the .25 will be in the gas barrel longer as travelling slower but more time to accelerate.

Almost, I think - people are worried that as it's in the barrel for longer, it gains more energy than the lighter round from the gas expansion; not more velocity than the lighter round.

Hold the bus....I just had a thought....

It is simple isn't it. Site rules with snipers say 500fps with a 0.2. (or what ever)

That's it then. That's all we need to worry ourselves with surely.

Yep.

[thekonassure]

Re: FPS limits and BB weights

Hold the bus....I just had a thought....

It is simple isn't it. Site rules with snipers say 500fps with a 0.2. (or what ever)

That's it then. That's all we need to worry ourselves with surely.

Yes but what sniper really uses a .20 ?? they all use .25`s or .30`s or heavier ok even if a .20 gets 500fps then a .30 in the same gun gets 500fps I`ll admit that after 30m`s its not going to hurt that much but if by mistake someone popped their head up and got smacked in the goggles by a 500fps .30 bb point blank .

Well most airsoft eye protection states that it`ll take either 400fps or 500fps point blank with a .20 if said person getting hit had the weakest kind of eye protection and it had taken a few hits before then took that .30 at 500fps well it could end bad

Also lets consider that said player had mesh goggles on ? ever had half a 500fps .30 bb in your eye ?

There`s so few gas snipers playing per day that its worth the extra what 2 mins to chrono them with the ammo they intend to use and work out what kind J`s its shooting at that`s all I`m saying.

[MUCKYMICK]

Re: FPS limits and BB weights

it cannot gain more energy the energy is spent trying to move the heavier mass of the bb ,the bb will then travel slower down the barrel and leaves the barrel at a slower fps the only thing that has any effect on how much impact force it has is how fast it is traveling and how heavy the bb is nothing else will effect that figure/outcome

[MUCKYMICK]

Re: FPS limits and BB weights

[QUOTE=thekonassure;821611]Yes but what sniper really uses a .20 ?? they all use .25`s or .30`s or heavierQUOTE]

And this is the reason why site ask that sniper /single shot weapons do not shoot more than 500fps on .2 bb you really are missing the point completly.
Using the .2 bb is the bench mark to calculate how hard that the gun is shooting at once this is established all other weight of bb's are within that site's limit's ,as you increase the weight of a bb you decrease how fast it will travel (fps) as every shot is fired with the same volume of propellant but you will increase the impact energy that bb has at the muzzle ,this energy will decrease very quickly as the bb has a greater mass and cannot travel as far as a lighter bb fired with the same volume of propellant so will impact the target with far less force ,possibly less impact force than a .2 bb fired from an aeg shooting 350fps at a target set at the same distance.
So please stop as this is getting silly.JUST USE A .2 BB TO CHRONO YOU GUN LIKE EVERY SITE IS ASKING YOU TO DO .THANK YOU