Vibe
22 Epperson Cricket
Pretty much...yep.
Which is why I ask. I would expect numbers and results of real wold shooting to show up more in these discussions.
Which is why I ask. I would expect numbers and results of real wold shooting to show up more in these discussions.
well.....
In the real world 1K is a loonngggg way away and stuff get's LOST over the distance.
Even @100yds with a full complement of windflags it's perty hard to spot all correlations betwixt the shot and the dot.
And anecdotal evidence is frowned on here. Documented empirical results are even given less weight than the "WHY" of stuff..... as it should be. Data should only support prediction, which is hard to do real-world as data are messy.
al
Vibe
22 Epperson Cricket
Sorry Bud...I can't resist....And THIS my friend is specifically why it can't be tangent..... look closely at the drawing to see fishtailing on Al's path....
If my 10min knee-jerk drawing needs editing I'll freakin' FIX IT!!
al
Are you saying that once out of the crosswind the bullet gets SUCKED back somewhat toward the original path?
Just yankin' your chain.
Sorry Bud...I can't resist....
Are you saying that once out of the crosswind the bullet gets SUCKED back somewhat toward the original path?
Just yankin' your chain.
yup
it is DRAG not planing...... surfboards plane.yankaway
al
T
tobybradshaw
Guest
See attached for the latest in applied ballistics (Tom Libby shot the 200yd group).
Toby Bradshaw
baywingdb@comcast.net
Toby Bradshaw
baywingdb@comcast.net
Attachments
T
Tony Shankle
Guest
more
Today's my anniversary so I will not be able to post until late tonight. But, some pics to stir the pot....(more on that gentle air cushion later Al)
This image shows the airflow around a 20-mm shell flying at about 500 m/sec (about 1600 ft/sec). The image was recorded using polarized light with an exposure time of 20 nanoseconds.
First picture of a bullet in flight. Notice once again the attitude....
and for those of you slightly confused....NOT a bullet in flight
Today's my anniversary so I will not be able to post until late tonight. But, some pics to stir the pot....(more on that gentle air cushion later Al)
This image shows the airflow around a 20-mm shell flying at about 500 m/sec (about 1600 ft/sec). The image was recorded using polarized light with an exposure time of 20 nanoseconds.
First picture of a bullet in flight. Notice once again the attitude....
and for those of you slightly confused....NOT a bullet in flight
Boyd Allen
Active member
Al,
Why bother with real data? Lets just see who can convince the most people without any, and then take a vote and declare the result to be reality. So little data....speaking of the wind...even numbers need to be confirmed by actual test, don't you think? I believe that the reason that this discussion has been so long is the simple lack of hard data. Yes, some things are really hard to prove. I love to speculate, but let us not confuse that, with what has been proven by actual demonstration...like in a wind tunnel. Wouldn't you think that all those aeronautical engineers would be pretty good with higher math, yet they still test. Are we better than they?
Why bother with real data? Lets just see who can convince the most people without any, and then take a vote and declare the result to be reality. So little data....speaking of the wind...even numbers need to be confirmed by actual test, don't you think? I believe that the reason that this discussion has been so long is the simple lack of hard data. Yes, some things are really hard to prove. I love to speculate, but let us not confuse that, with what has been proven by actual demonstration...like in a wind tunnel. Wouldn't you think that all those aeronautical engineers would be pretty good with higher math, yet they still test. Are we better than they?
Boyd,
I can't agree re lack of hard data. I'm not disputing any work done in a wind tunnel and I'm not saying NOT to test. It's just that by definition it's "testing"..... the horse still has to push the cart!
This is old stuff, really..... it IS well understood by the engineers involved
we're (or at least I'm) just lay ignorant..... it's not our field.The folks at Aberdeen, guys like Vaughn, McCoy, Borden and Jackson, do fully understand this stuff.... there's no confusion there. McCoy's stuff isn't speculative. It's the folks who try to understand and then teach the stuff who fail. Sierra's techs aren't professional ballisticians, they're bulletmakers who study ballistics as a hobby. This isn't a slam on them, but it doesn't invalidate the work done by folks who do it for a living. The guys at Sierra have always been great about acknowledging when they're confused. And they've come a long way.
The problem lies with US, we non-ballisticians who're striving to grasp it. It's like if I decided to design a warship or a suspension bridge..... it's not that the experts out there are confused, it's that most of us (ME anyway..
) are in a little over our heads here. Guys like me would generally have to rely on testing to destruction for the first couple bridges..... just keep driving heavier trucks over...... "oops...gotta' design a little heavier beam there....."
So once I've got a building or bridge designed I call in the numbers guys to spec it. I don't test it. The testing was done years ago.
Back when "lubricating" bullets was hailed as the Second Coming we all saw all sorts of empirical testing and many conclusions were drawn. Some folks like the late Dan Hackett used this home testing to dispute folks like Harold Vaughn. I chose to believe Harold Vaughn mainly because his credentials were better, I did NOT take the time to understand the physics. But I also believe that if Dan had presented his case with something other than "there's a lot about ballistics we don't understand" he would have gained credibility. As I try to digest "Modern Exterior Ballistics: The Launch and Flight Dynamics of Symmetric Projectiles" I don't see much that's "misunderstood."
Either McCoy's a helluva salesman or he KNOWS whereof he speaks!
A lot of engineers don't understand their stuff in depth either...... just like anywhere else some are better than others. I deal with building engineers every day (you know where I'm going with this! You've done the same thing..
) Some of them are really bright guys, some of them are just number crunchers applying formulae. The number cruncher guys often start with a bad premise and build from there.... doesn't invalidate the formulas, just the usage. GIGOI'm not breaking any ground here, just striving to understand.
Nor am I arguing with the ballistics guys..... I'm just casually discussing with my peers. Sometimes not so casually.....
..... Ol' Vibe'rator and Toby the Tiger and Keith dished me a healthy helping of Creaux au Gratin recently because I couldn't (STILL struggling here, reading...studying) understand that a bouncy ball imparts more energy to something than a lead sap of equal mass...... I STILL have egg on my face from the muzzle brake thread..... I STILL wonder about driving pile with a rubber bumper...but ohh well. I started off good, just got into the deeper end and floundered...
Until I can prove differently I have to go with vibe Toby Keith and others..... My intuition was just wrong.
But I still enjoy this stuff
al
Boyd Allen
Active member
Vibe
22 Epperson Cricket
Pretty much like a reference chart.
T
Tony Shankle
Guest
Gene Beggs
Active member
Good evening guys; I'm back!
Yep, crawled out of the tunnel this evening after two exhaustive days of top secret experiments for,,,, well, I could tell you but then I'd have to kill ya'. (Yeah, right Beggs, uh huh; your so full of it. )
This discussion of wind drift has been most interesting. Those who have been with us from the beginning are familiar with the scenario in which we are shooting at 1000 yards. In the first 500 yards, wind is calm. Between 500 and 600 yards, there is a direct crosswind at 10 mph and from 600 yards to the target, wind is calm.
As Alinwa says, "Fugetabout the first 500 yards; nothing is happening," I agree.
Upon entering the crosswind at 500 yards, everyone agrees that the bullet will make a turn and establish a wind correction angle to compensate for the crosswind component; but does the nose of the bullet turn into the crosswind or away from it? Here's where some of you are getting confused.
Of course, the nose of the bullet turns in the direction from which the wind is blowing; if the crosswind is blowing from left to right, the nose of the bullet turns to the left! This is a fact chiseled in stone and if you believe otherwise, you are mistaken. I will not argue this point with you and I'll make no further attempt to convince you otherwise. If you disagree with me on this point, I suggest you contact Bryan Litz, the chief ballistician at Berger/J-4. Bryan's credentials are impressive; he is not only very well educated, but he is also a terrific shooter and the present Palma National Champion.
With the written word, here on a public forum, it is very difficult to clear up some misconceptions.
Later
Gene Beggs
Yep, crawled out of the tunnel this evening after two exhaustive days of top secret experiments for,,,, well, I could tell you but then I'd have to kill ya'.
(Yeah, right Beggs, uh huh; your so full of it. )This discussion of wind drift has been most interesting. Those who have been with us from the beginning are familiar with the scenario in which we are shooting at 1000 yards. In the first 500 yards, wind is calm. Between 500 and 600 yards, there is a direct crosswind at 10 mph and from 600 yards to the target, wind is calm.
As Alinwa says, "Fugetabout the first 500 yards; nothing is happening," I agree.
Upon entering the crosswind at 500 yards, everyone agrees that the bullet will make a turn and establish a wind correction angle to compensate for the crosswind component; but does the nose of the bullet turn into the crosswind or away from it?
Here's where some of you are getting confused. Of course, the nose of the bullet turns in the direction from which the wind is blowing; if the crosswind is blowing from left to right, the nose of the bullet turns to the left! This is a fact chiseled in stone and if you believe otherwise, you are mistaken. I will not argue this point with you and I'll make no further attempt to convince you otherwise. If you disagree with me on this point, I suggest you contact Bryan Litz, the chief ballistician at Berger/J-4. Bryan's credentials are impressive; he is not only very well educated, but he is also a terrific shooter and the present Palma National Champion.
With the written word, here on a public forum, it is very difficult to clear up some misconceptions.
Later
Gene Beggs
T
Tony Shankle
Guest
Good to have you back Gene
I didn't realize anyone was still doubting (or ever did) that the bullet turns into the wind. I thought we were discussing what happens when it comes out of that wind at 601 yards???
While I am on that same side of the "ribber" as Al, I am there for slightly different reasons. Al's drawings (a masterpiece i might add) shows the deflection after the 601 mark as a result of a new vector after the wind has stopped. Like Al, I know it continues to deflect as I have seen it many times on my 1000 yard range (I have a break in the trees from 500 to 650 yards) but I don't believe from my studies that it is a "where's it pointing" issue as much as a momentum issue. The results are the same as Al's but the reason is different. I obtained Rinkers address and I am sending him a letter to ask his help on the issue.
Hope you enjoyed your company Gene.
Tony
I didn't realize anyone was still doubting (or ever did) that the bullet turns into the wind. I thought we were discussing what happens when it comes out of that wind at 601 yards???
While I am on that same side of the "ribber" as Al, I am there for slightly different reasons. Al's drawings (a masterpiece i might add) shows the deflection after the 601 mark as a result of a new vector after the wind has stopped. Like Al, I know it continues to deflect as I have seen it many times on my 1000 yard range (I have a break in the trees from 500 to 650 yards) but I don't believe from my studies that it is a "where's it pointing" issue as much as a momentum issue. The results are the same as Al's but the reason is different. I obtained Rinkers address and I am sending him a letter to ask his help on the issue.
Hope you enjoyed your company Gene.
Tony
Boyd Allen
Active member
Where it's pointing question...
On something like a typical Matchking, where is the center of pressure relative to the center of gravity? When the force of a cross wind is applied from the side, at what point is the force considered to have been applied? If a bullet is turned, by applied force, where is the pivot point?
Another question
When the wind blows on a cylinder, at right angles to its axis, what happens to the air pressure on the windward and lee sides?
On something like a typical Matchking, where is the center of pressure relative to the center of gravity? When the force of a cross wind is applied from the side, at what point is the force considered to have been applied? If a bullet is turned, by applied force, where is the pivot point?
Another question
When the wind blows on a cylinder, at right angles to its axis, what happens to the air pressure on the windward and lee sides?
Gene Beggs
Active member
Okay Tony, we will continue,,
,,,,,with our discussion.
Toby Bradshaw provided us with a number to use for the crosswind correction angle. His calculations showed the bullet turns only .48 degrees upon entering the 10 mph crosswind at 500 yards Yes, that's correct; less than one half of one degree!
Let's assume the straight-line over-the-ground course from the muzzle to the target at 1000 yards is due north or better referred to as heading '0' degrees. Our bullet starts out on a heading of '0' degrees, its ground track is also '0' degrees as there is no crosswind in the first 500 yards. If the bullet is launched at 3000 fps it feels a relative wind right on the nose of 3000 fps. Of course, it is constantly decellerating after leaving the muzzle.
Reaching 500 yards, our bullet enters a direct crosswind from left to right at 10 mph. The crosswind results in a bit of drag on the left side of the bullet and it turns half a degree left, into the crosswind, to streamline itself with the new relative wind.
The bullet is now flying perfectly streamlined thru the airmass on a heading of 359.5 but its nose is pointing half a degree left of course relative to the ground. If not for the fact that it is constantly slowing down, the bullet would not drift at all!
As velocity continues to decrease, on a heading of 359.5, the bullet begins to drift downwind over the ground. Heading does not change but ground track does, and that's what we are concerned with; ground track.
Perhaps the reason so many have trouble accepting my explanation is because they think the bullet turns much farther than it actually does. Of course, I realize we often exagerate things to make a point, but Alinwa's drawing is a bit misleading in that it depicts the wind correction angle as approximately 30 degrees! No one would believe a bullet turns 30 degrees back to its original heading upon exiting the crosswind at 601 yards and of course, it doesn't. It was only crabbed (relative to the ground) half a degree (heading 359.5) to begin with so when it exits the crosswind at 601 yards, the bullet turns half a degree to the right, streamlines itself with the new relative wind and is now on its original heading of '0' degrees. From 601 yards to the target winds are calm, there is no crosswind component so there can be no drift.
I'm getting tired; we will continue our discussion tomorrow.
Good night all.
Gene Beggs
,,,,,with our discussion.
Toby Bradshaw provided us with a number to use for the crosswind correction angle. His calculations showed the bullet turns only .48 degrees upon entering the 10 mph crosswind at 500 yards
Yes, that's correct; less than one half of one degree!Let's assume the straight-line over-the-ground course from the muzzle to the target at 1000 yards is due north or better referred to as heading '0' degrees. Our bullet starts out on a heading of '0' degrees, its ground track is also '0' degrees as there is no crosswind in the first 500 yards. If the bullet is launched at 3000 fps it feels a relative wind right on the nose of 3000 fps. Of course, it is constantly decellerating after leaving the muzzle.
Reaching 500 yards, our bullet enters a direct crosswind from left to right at 10 mph. The crosswind results in a bit of drag on the left side of the bullet and it turns half a degree left, into the crosswind, to streamline itself with the new relative wind.
The bullet is now flying perfectly streamlined thru the airmass on a heading of 359.5 but its nose is pointing half a degree left of course relative to the ground. If not for the fact that it is constantly slowing down, the bullet would not drift at all!
As velocity continues to decrease, on a heading of 359.5, the bullet begins to drift downwind over the ground. Heading does not change but ground track does, and that's what we are concerned with; ground track.
Perhaps the reason so many have trouble accepting my explanation is because they think the bullet turns much farther than it actually does. Of course, I realize we often exagerate things to make a point, but Alinwa's drawing is a bit misleading in that it depicts the wind correction angle as approximately 30 degrees! No one would believe a bullet turns 30 degrees back to its original heading upon exiting the crosswind at 601 yards and of course, it doesn't. It was only crabbed (relative to the ground) half a degree (heading 359.5) to begin with so when it exits the crosswind at 601 yards, the bullet turns half a degree to the right, streamlines itself with the new relative wind and is now on its original heading of '0' degrees. From 601 yards to the target winds are calm, there is no crosswind component so there can be no drift.
I'm getting tired;
we will continue our discussion tomorrow. Good night all.
Gene Beggs
No, I don't think our reasons are different Tony
As I've said over and over..... where the bullet points is incidental to the situation, "an artifact" is the phrase I use. Round balls act exactly the same way, but no pointing.Getting fixated on the bullet's attitude is a mistake. It's attitude is not WHY it drifts.
al
M
model14
Guest
"The bullet is now flying perfectly streamlined thru the airmass on a heading of 359.5 but its nose is pointing half a degree left of course relative to the ground. If not for the fact that it is constantly slowing down, the bullet would not drift at all!"
Gene,
I was doing okay until the above statement. In my pea-brained mind the airmass is moving right, the bullet is within the airmass, and therefore the bullet will drift right even if there is no slowing down due to drag. Please explain your reasoning behind "If not for the fact that it is constantly slowing down, the bullet would not drift at all!" If I am standing at the firing line and observing the bullet (superman eyes) relative to the target, I will observe a right drift. I agree it will drift much less if there is little lag, but it will still be seen as drifting,
Thanks,
Richard
Gene,
I was doing okay until the above statement. In my pea-brained mind the airmass is moving right, the bullet is within the airmass, and therefore the bullet will drift right even if there is no slowing down due to drag. Please explain your reasoning behind "If not for the fact that it is constantly slowing down, the bullet would not drift at all!" If I am standing at the firing line and observing the bullet (superman eyes) relative to the target, I will observe a right drift. I agree it will drift much less if there is little lag, but it will still be seen as drifting,
Thanks,
Richard
Boyd Allen
Active member
Al,
Atta boy!
As to discussions about what would happen if a bullet did not slow down, rockets accelerate from launch, and yet I believe that they are moved by the wind. (launch conditions and all of that) In a discussion about bullets, IMHO this whole "what if" is just off topic, since any bullet is always slowing down after it leaves the barrel. I believe that this topic is difficult enough without these excursions off topic. I cringe every time I read some "expert" taking the leap from lag time to a statement that if a bullet didn't slow down that it would not experience wind drift. First of all this is an unwarranted conclusion, secondly it is an impossible situation because the only way that a bullet would not slow down is if there was no atmosphere, a condition that precludes the existence of wind. I do not mention this to argue the point but to point out how straying off topic can be a distraction, rather than assisting with an explanation. Speaking of which, it would seem to me that the wall we must all run into is that much of this discussion has to be about what we imagine happens, because we have no way to directly observe what is happening, and so we imagine that it is like something else that IS observable. The trouble is that using this method may, and almost assuredly does, lead us astray, in most cases, and we end up arguing about an example that is not the same in the first place. We need more hard data, and fewer "is likes". Just one opinion...
Atta boy!
As to discussions about what would happen if a bullet did not slow down, rockets accelerate from launch, and yet I believe that they are moved by the wind. (launch conditions and all of that) In a discussion about bullets, IMHO this whole "what if" is just off topic, since any bullet is always slowing down after it leaves the barrel. I believe that this topic is difficult enough without these excursions off topic. I cringe every time I read some "expert" taking the leap from lag time to a statement that if a bullet didn't slow down that it would not experience wind drift. First of all this is an unwarranted conclusion, secondly it is an impossible situation because the only way that a bullet would not slow down is if there was no atmosphere, a condition that precludes the existence of wind. I do not mention this to argue the point but to point out how straying off topic can be a distraction, rather than assisting with an explanation. Speaking of which, it would seem to me that the wall we must all run into is that much of this discussion has to be about what we imagine happens, because we have no way to directly observe what is happening, and so we imagine that it is like something else that IS observable. The trouble is that using this method may, and almost assuredly does, lead us astray, in most cases, and we end up arguing about an example that is not the same in the first place. We need more hard data, and fewer "is likes". Just one opinion...