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Post by X on Jun 25, 2014 13:40:12 GMT -5
I don't think it's that simple (remember inertia = mass). A .40g bb thrown at someone will not do more damage than a .20g bb shot at 1000FPS. In that example the .40g bb has greater inertia, but less momentum and less kinetic energy. After checking out several physics forums it seems the problem is very complex, but in general KE is more important.
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Post by blackhawkranger on Jun 25, 2014 14:54:28 GMT -5
I see where you're coming from with this creep business now... However the gains in joules at sub 400fps (with .2's) would be minimal all things considering. I mean at the end of the day we're firing mass produced plastic balls down a brass tube so scientific accuracies are somewhat out the window right? And that's before we take barrel length, diameter, air leakage out the hop unit, hop rubber imperfections, shot to shot fps consistency and finally variations in chrono readings (yea the chronos we use are good but hardly lab grade equipment). On the other side of the coin isn't this creep still just as applicable for AEG's/GBB so why does it seem to be directed at P* systems? (Not being argumentative but just wondering if there's a factor I've overlooked as I said I know very little about them) I mean I know one of the big things with GBB pistols is hi flow valaves on magazines so wouldn't the same be true? (Although yes to a lesser extent I guess due to barrel length generally being much shorter). But what about gas powered sniper rifles during the summer months or using propane/red gas etc And with the plethora of afteramrket parts for AEG's out there I'm sure the same is true there (different brand cylinders, pistons etc have different specs forcing a higher/lower amount of air down the barrel. I mean granted you can't programm it like a polarstar but the same is true none the less.) I'm not saying there aren't gains to be had however I think were only looking at the extreme end of the scale running high fps and a long barrel but that's instantly combated by chronoing with the weight bb that's going to be actually used right? Don't get me wrong I'm neither for or against as it's not going to affect me so dont take this as me being argumentative but I'm genuinely interested in the who, what, why, when and where's
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Post by Stinger on Jun 25, 2014 15:47:03 GMT -5
I don't think it's that simple (remember inertia = mass). A .40g bb thrown at someone will not do more damage than a .20g bb shot at 1000FPS. In that example the .40g bb has greater inertia, but less momentum and less kinetic energy. After checking out several physics forums it seems the problem is very complex, but in general KE is more important. I meant when they are carrying the same amount of energy Of course a 0.20-gram BB at 1000 FPS will do more damage than a 0.40-gram BB.
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Post by Gunslinger on Jun 25, 2014 18:36:48 GMT -5
You guys are nerds. My brain is oozing out of my nose while drool on my keyboard.
Also, question as far as creep and air X barrel length X bb weight (optimizing "volume" for the inner barrel length being used), I just picked up a 417D.
Now, with .20 gram bb's with the hop up turned all the way off the bb raises like I have it on fully pretty much within a few feet maybe 15. From my interpretation of how things have been layed out so far the barrel was "over volumed" for .20 gram bb's, would that be a correct assumption regardless of inner barrel length (stock). When even using .28 gram bb's and still the hop up all the way off I get a closer to a level flight path making me believe that I am getting closer to evening the "volume" of air and the bb weight being used along with inner barrel length.
SO I feel if I use a heavier gram bb with the hop up off still and I can actually get the BB to drop very soon after leaving the barrel tip before involving the hop up would I then be closer to equalizing the volume of air to BB weight ratio?
Just something that I had pop in my head as I have been fallowing the logic and scientific equations of this discussion.
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Post by Marshy on Jun 25, 2014 19:11:31 GMT -5
AEGs produce a single puff of air when the piston comes forward. gas pistols and sniper rifles do the same when the trigger is pulled, the nozzle mechanically activates releasing a puff of air. When a polarstar is fired, the nozzle is activated electrically rather than mechanically, from what I understand. This allows the length of the burst (rather than a puff) to be adjusted. When the length is adjusted longer than the standard puff from an aeg, it allows air to continually flow even after the bb leaves. If the air flow is set to accelerate until a .30 leaves the barrel, it effectively tunes the fps of the .30 to be higher than standard puff from a cylinder would allow. When a .20 is fired from the same gun, air is released out the barrel slightly longer than what it takes for the bb to leave the barrel, causeing air to escape out after the bb leaves. this causes the .20 to still accelerate to the end of the barrel, but fps is wasted. This is essentially what leads to the power creep. It allows the .20 to crono normal, but gives higher FPS to the increased weights.
Source: Don't know polarstars, but science says I'm right.
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echo5
New Member
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Post by echo5 on Jun 25, 2014 19:11:57 GMT -5
I see gunslingers logic, and think that it's really a compelling argument. Is hop up irrelivent until air volume equalization is achieved, and is this the way we should approach setting not only a P* but any aeg or gbb rifle. Then would we be able to ascertain what appropriate weight should be using? I think its great food for thought as far as setting any airsoft rifle, and will actually attempt to set guns using this method. But unfortunately it still doesn't change the fact that until there is a scientific measurement of force that directly relates to weight, barrel length, diameter of said barrel, and psi force propelling the projectile, there is not a fair and equal way to chrono a P* except with a generic weight and an idea of acceptable joules or force. What's good for the goose should be good for the gander. Chrono an aeg with .25's and achieving 364fps, and read what the joules are, then make that your benchmark.
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Post by Stinger on Jun 25, 2014 19:16:38 GMT -5
"...there is not a fair and equal way to chrono a P* except with a generic weight and an idea of acceptable joules or force. What's good for the goose should be good for the gander. Chrono an aeg with .25's and achieving 364fps, and read what the joules are, then make that your benchmark." I agree. Polarstars should have to fall under the same joule ratings as AEGs. In an ideal world, everyone should chrono with heavy weight BBs just to "level the playing field" and make it fair for all (even though AEG energy creep is low). At the very least, P*s need to be chronographed using heavy, known-weight BBs. And then spot-checked in the same manner.
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echo5
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Post by echo5 on Jun 25, 2014 19:21:32 GMT -5
AEGs produce a single puff of air when the piston comes forward. gas pistols and sniper rifles do the same when the trigger is pulled, the nozzle mechanically activates releasing a puff of air. When a polarstar is fired, the nozzle is activated electrically rather than mechanically, from what I understand. This allows the length of the burst (rather than a puff) to be adjusted. When the length is adjusted longer than the standard puff from an aeg, it allows air to continually flow even after the bb leaves. If the air flow is set to accelerate until a .30 leaves the barrel, it effectively tunes the fps of the .30 to be higher than standard puff from a cylinder would allow. When a .20 is fired from the same gun, air is released out the barrel slightly longer than what it takes for the bb to leave the barrel, causeing air to escape out after the bb leaves. this causes the .20 to still accelerate to the end of the barrel, but fps is wasted. This is essentially what leads to the power creep. It allows the .20 to crono normal, but gives higher FPS to the increased weights. Source: Don't know polarstars, but science says I'm right. Alright, I will agree with this and disagree. I know, playing both sides of the fence is stupid, but this is why I say this. You're now speaking of a measurement if time. The time that the piston pulls back, loads air, and then pushes it forward. That is a unit of time based off of gear ration, piston length, and spring tension. P* just do it with a poppet. When you adjust your FCU you are adjusting poppet dwell in milliseconds, and the chamber that holds the air after the poppet releases it before it goes through the nozzle is about the same size if not smaller than a regular aeg. Is there way to test it and measure the air that comes out in a recordable volume? Then we could settle this once and for all. I've enjoyed the debate, but I can't do it anymore. I appreciate all the insight, and good conversation. I have to move on from this topic as I don't see a viable resolution.
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Post by Mosin on Jun 25, 2014 20:04:02 GMT -5
As I said in the thread for SCEN: Maelstrom, it doesn't matter what weight they come in at because even if they say .30 and they switch to .43 it only hurts themselves if we spot check on field. Adversely, if a player has his rifle tuned to 1.55 joules with a .3 and intends on staying with a .3, I don't want to put in a .43 and tell them they're shooting too hot, because they technically are not.
It just comes down to spot checking on field, as well as initial chronograph. Unless I'm seriously missing something, there is nothing that can change that. You come up to chrono with what you intend on using for the day, and you shoot under 1.55 joules. Whatever bb weight that happens to be doesn't matter, because I'll spot check you on field and if I see you coming in at 2.09 joules because you increased the bb weight, you're off the field for being a safety violator.
If you do chrono at 1.55 joules with a certain weight, and want to switch the weight of the bb, simply go back to chrono or locate a ref on field and ask if they can escort you to chrono to re-tag so you can readjust whatever you have to in order to come in under 1.55 joules.
Stop nuking the shit out of this.
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Post by Stinger on Jun 25, 2014 20:07:53 GMT -5
Mosin, the only possible issue I can see with that is that you will have to verify somehow that the BB weight they say they are using is the real weight that they are using. Both when they first chrono, and when you spot-check them. The only way to do that, that I can think of, is to provide the ammunition yourself. That way, you know what weight they're using.
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Post by Mosin on Jun 25, 2014 20:17:54 GMT -5
How could it go wrong? If I say I'm shooting lighter than I really am, I screw myself over when you spot check me on field. If I say I'm shooting heavier than I am, then there should be no reason when I spot check you it should be higher. We've already established that P*s only fluctuate about 5-6 fps, or maybe 0.01 of a joule using the same weight bb.
Tell me how you can cheat that?
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Post by Stinger on Jun 25, 2014 20:24:49 GMT -5
How could it go wrong? If I say I'm shooting lighter than I really am, I screw myself over when you spot check me on field. If I say I'm shooting heavier than I am, then there should be no reason when I spot check you it should be higher. We've already established that P*s only fluctuate about 5-6 fps, or maybe 0.01 of a joule using the same weight bb. Tell me how you can cheat that? One of us is misunderstanding the other. I'm not quite sure which one of us that is. Okay, this is how I would cheat that if I wanted to: I go to the field with two weights of ammunition: 0.20-gram BBs, and 0.40-gram BBs. Let's say my P* (I don't really even have one) is tuned to creep up by 0.3 joules (someone on here already proved that's easy, but I forgot who and where). I chrono with my 0.20-gram BBs, telling you that I am using 0.20-gram BBs. I shoot at 1.55J. When I go on the field, I switch to my 0.40-gram BBs. I am now shooting at 1.85J (which is over your limit). When you spot check me, I tell you I'm still using 0.20-gram BBs. You chrono me, calculate energy, and will end up with a joule rating lower than what I originally chrono'd with (because my FPS will be lower due to the heavier BB). But, how are you gonna know? As far as you know, I'm under the 1.55J limit, and I keep playing, even though I'm really shooting 1.85J. Does that make sense?
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Post by Mosin on Jun 25, 2014 20:34:49 GMT -5
Because we've established that polarstars don't fluctuate that much. If you told me your P* naturally fluctuates .3 joules I'd call you a liar.
With chronographs you don't look at fps for P*, you look at joule rating, so no conversion is needed.
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Post by Stinger on Jun 25, 2014 20:36:53 GMT -5
Because we've established that polarstars don't fluctuate that much. If you told me your P* naturally fluctuates .3 joules I'd call you a liar. Is there a way to calculate energy without knowing the mass of the BB? Because as far as I know, if I didn't tell you the correct mass of my BB, you would have no idea my P* fluctuated 0.3J.
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Post by Marshy on Jun 25, 2014 20:37:36 GMT -5
No.
You're missing the point. it's not about energy produced by the gun, it's about potential energy being converted to kinetic energy. If you have 1 joule of potential energy for forcing a bb down the barrel, and the air escapes for 10miliseconds, but it only takes 8 miliseconds for that bb to escape the barrel, you have .2j left over and the bb holds an energy of .8j. The .2j is simply wasted out the end of the barrel similar to how powder from a 357magnum is wasted out the barrel of a 1 1/8" barrel on a RS handgun.
Obviously this shit is all just rounded around, and I have no fucking clue how long it takes a BB to leave a 300mm barrel, and don't feel like going through calculations and shit, I just rounded numbers to make it easier.
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