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Post by luke213 on Mar 13, 2015 18:23:53 GMT -5
Well I can't say I've tested the theory don't have a chrono currently planning on building one but likely it won't handle this sort of test. If I end up borrowing one then I'll do it. I believe I read that on Airsoft Sniper forums but I could be mistaken and it seemed like the guys had the numbers and info to back it up.
Luke
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Post by Gimpalong on Mar 13, 2015 18:25:18 GMT -5
Even in AEGs, the benefit of using a heavier BB isn't solely to overcome wind resistance. In fact, I'd wager the impact of wind resistance on a .20 and a .25 are negligibly different. The main reason to use a heavier BB is because even AEGs experience joule creep to a degree. Yes, hop-ups tend to work better with heavier weight rounds, but the main benefit of the heavier round is the joule creep inherent in the added weight. At some point though adding weight will absolutely result in decreased range. Based on this person's results I have to disagree. www.pstartalk.com/archive/index.php/t-374.htmlWait, what are you disagreeing with? Because from that post: and Clearly demonstrate that AEGs experience joule creep to a degree.
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Post by Tank on Mar 13, 2015 18:26:39 GMT -5
EDIT: Also if your testing I'd love to see a chrono test at the muzzle and then one at 50ft. if someone has a traditional firearm chrono which should be a big enough target to hit at that distance. That might shed some light on it. I love your line of thinking! X and I have been meaning to do this test for over a year. Now he has a p*, I have a radar chrono, so we can chrono at different ranges, we are both engineers (one by occupation, the other by degree, so we are anal in our testing strategy), we have multiple weight BBs, and I'm buying a scale that measures in increments of .001 g. We will adjust the p* for each BB weight, so the muzzle energy (in joules, of course) is the same for each weight. We will measure at muzzle, and at least two other distances. We will do it with hop up off, and properly hoping. Then we will see what the furthest range is, this will be the most challenging part. I'm not saying it will be done tomorrow, but we will do this very soon. I'm dieing to see the real world results.
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Post by X on Mar 13, 2015 18:30:20 GMT -5
Wait, what are you disagreeing with? Because from that post: and Clearly demonstrate that AEGs experience joule creep to a degree. That's the equivalent of 9 and 4 FPS (w/.20) respectively (within margin of error for some chronos I'd say) and you cut out the part where every increase in weight following that sees a decrease in energy. I'm disagreeing with the fact that people switched to .25s primarily for the extra energy. People switched to them because they're not as affected by wind and tend to hold tighter groupings.
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Post by Gimpalong on Mar 13, 2015 18:34:25 GMT -5
Well, yeah. But the point remains that AEGs do experience a limited amount of joule creep. As demonstrated, if you go from a .20 to a .25 even an AEG will experience an increase in output energy. And, yes, as you increase weight the effect will taper off, but that's also true of Polarstars. Angus only measured out to .40s, but an decrease in energy must certainly happen, right?
Why do heavier rounds cause "better groupings?" Why are they not as affected by wind? A) Yes, because they have more mass, but also B) because they're carrying more energy.
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Post by X on Mar 13, 2015 18:40:08 GMT -5
Well, yeah. But the point remains that AEGs do experience a limited amount of joule creep. As demonstrated, if you go from a .20 to a .25 even an AEG will experience an increase in output energy. And, yes, as you increase weight the effect will taper off, but that's also true of Polarstars. Angus only measured out to .40s, but an decrease in energy must certainly happen, right? Why do heavier rounds cause better groupings? Why are they not affected by wind? A) Yes, because they have more mass, but also B) because they're carrying more energy. By those results though the effect doesn't taper off it literally goes in the opposite direction the projectiles begin loosing energy, which I would attribute to under volume. At .30 and above those AEGs actually have less energy than with a .20. Edit: The ONLY things that affect the projectiles deviation from wind is the projectiles mass, the winds mass and velocity, and the projectiles drag coefficient. If a projectile was moving forward at 100 FPS and it was subjected to a 90 degree crosswind it would move exactly the same distance laterally if it were moving at 500 FPS. The amount of energy is technically irrelevant. The only thing that makes a difference is that the BB gets to the target faster and therefor is subjected to less wind. But again that's negligible when were talking a lousy 4 FPS.
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Post by Gimpalong on Mar 13, 2015 18:46:25 GMT -5
Right, absolutely. I don't disagree with you. Eventually, as you increase the weight of round that an AEG is firing the amount of energy being output will decline. But I'd argue that that is also true for Polarstars. At some point, as you increase the weight of the round, the energy put out by a Polarstar will also start to decline. Joule creep can't be infinite, right? I'm honestly curious.
I'm willing to concede that joule creep might not be the sole reason why AEG users would use heavier rounds. But I think how effectively the round travels through the air has a lot to do with its weight in addition to energy creep.
edit: So what you're arguing is that the mass is the most important factor? I'd agree with that.
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Post by X on Mar 13, 2015 18:50:55 GMT -5
Right, absolutely. I don't disagree with you. Eventually, as you increase the weight of round that an AEG is firing the amount of energy being output will decline. But I'd argue that that is also true for Polarstars. At some point, as you increase the weight of the round, the energy put out by a Polarstar will also start to decline. Joule creep can't be infinite, right? I'm honestly curious. I'm willing to concede that joule creep might not be the sole reason why AEG users would use heavier rounds. But I think how effectively the round travels through the air has a lot to do with its weight in addition to energy creep. In this context nothing is truly infinite, however practically speaking with a big bottle filled with 3000 PSI of air on your back you essentially have infinite air volume which is the primary factor. The amount of air in that tank would fill an 8" x 8" x 8" cube. That's a lot of air you can push down that barrel. At 80 psi its about 1.6 cubic foot. Still a lot of air you could theoretically push down a barrel.
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Post by Gimpalong on Mar 13, 2015 18:54:42 GMT -5
Sure, we could have a 100m long barrel and enough air to fill it, but for all practical purposes there has to be a point where joule creep reverses and the amount of energy being imparted to the BB declines. It would be interesting to see where this point lies with a standard length 363mm M4 barrel. You think we'd still see increases in energy once we hit 1 gram? There's probably some fancy, physic-y way to calculate all that.
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Post by X on Mar 13, 2015 18:59:20 GMT -5
Yes I think no matter how dense of a BB you could put in the gun you could get more energy then that of a lighter object. The problem is gravity doesn't give a shit how much mass or energy you got. It still accelerates you at the same rate towards earth. Unless of course it was like a black hole which would then pull the earth, but again that's not relevant.
By the way I think were a bit off topic here. We have a useable system for measuring a BBs energy. For the purpose of our ruleset joule creep doesn't matter if you chrono the BB being used. Its really irrelevant.
The only thing I think is worth talking about is if Joules truly equal pain. Which I honestly think they do not. I bet that a .12 at the muzzle hurts more than an .40 with the same joules.
1 Joule is a .12 at 424 and a .40 at 232.
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Post by luke213 on Mar 13, 2015 19:21:34 GMT -5
The only thing I think is worth talking about is if Joules truly equal pain. Which I honestly think they do not. I bet that a .12 at the muzzle hurts more than an .40 with the same joules. I'm not so sure about that, but I would say there is a fair amount of ballistic evidence in real steel that could apply here in how energy is transferred. Only downside is that we're talking penetration rather than surface impacts. But I suspect the heavier projectile transmits more energy but that may have allot to do with the theory that it's traveling faster when it impacts. IE it's still carrying more energy at any distance but there is probably a correlation between the average engagement distances in airsoft and the energy the projectile still has at those ranges. Or at least spitballing thats what I think. Luke
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Post by X on Mar 13, 2015 19:28:28 GMT -5
The only thing I think is worth talking about is if Joules truly equal pain. Which I honestly think they do not. I bet that a .12 at the muzzle hurts more than an .40 with the same joules. I'm not so sure about that, but I would say there is a fair amount of ballistic evidence in real steel that could apply here in how energy is transferred. Only downside is that we're talking penetration rather than surface impacts. But I suspect the heavier projectile transmits more energy but that may have allot to do with the theory that it's traveling faster when it impacts. IE it's still carrying more energy at any distance but there is probably a correlation between the average engagement distances in airsoft and the energy the projectile still has at those ranges. Or at least spitballing thats what I think. Luke Yeah I honestly don't know. I'm just thinking higher velocity does not give the skin time to disperse the energy thus causing penetration. The more massive object is more resistant to being slowed down though. Could go either way. I'm just not convinced yet that joules share a linear relationship with pain and we seem to have jumped to that conclusion.
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Post by Coldwave on Mar 13, 2015 20:02:44 GMT -5
You'd have to have somewhere in the neighborhood of 5-15 people to test that theory. Stand at a pre determined distance from the shooter, face the shootee away from the shooter. Provide hearing suppression so as not to distinguish which weapon you are being shot with and ask which one hurt more and note the mark. Then you would have a legitimate reading.
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Post by luke213 on Mar 13, 2015 20:03:03 GMT -5
I'm thinking that joules might actually equate to pain but that only makes sense to me if the heavier projectile is carrying more energy at a distance. Since seldom are shots up close, so if that is correct then it makes allot of sense that a heavier projectile hurts more since it's still carrying more energy.
Honestly I don't have a clue either, this is just purely based on what I've seen and felt and honestly my experience with heavier BB weights and their effects is fairly limited. Back in the day we used .2g BB's almost exclusively and now I've been messing with everything from .20-46g stuff in all sorts of velocities so it's given me a bit more experimenting then I used to have;)
Luke
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Post by Stinger on Mar 13, 2015 20:27:16 GMT -5
For those of you discussing AEG joule creep: It's a real thing.
A guy I know built what is called a "joule-creeper," and AEG meant to abuse the system, just to prove he could. 165mm inner barrel widebore, type-0 (closed) cylinder, M150 spring. 320 FPS on 0.2-gram and 400 FPS on a 0.3-gram BB. THAT should scare you. Because it's easy to take that on the field and use it.
Like I said a while pack in the P* discussion thread we had, while I was trying to find ways to break Mosin's chrono method: If someone is smart enough and dedicated enough, they will be able to do it. It just takes a knowledge of the gun, the physics, and the willingness to cheat.
What really needs to be done is some serious testing and then planning of a system that does not rely on the player being honest. Because if you are relying on the player's honesty, why the hell are you checking them in the first place? Checking is to find cheaters.
Also, more joules = more pain. That's more kinetic energy hitting you and therefore more damage to your body.
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