Originally Posted by Reloader
This is not to flame anyone, just to state some facts:
Spinning tops have absolutely no validity when we are talking bullets. A spinning top "goes to sleep" in a different spot every time.
A large grouping load can NOT get smaller at longer distances, it is physically impossible. Simply put, a bullet leaves on a path once stabilized and only is effected by the atomosphere in which it flys(IE: wind, pressure, gravity, etc).
Some bullets will leave a bbl unstabilized and can become stabilized during flight, once they become stabilized they fly on that path only effected by the atmosphere and elements apllied. These unstable bullets do not magically go back to the path the shooter wants them to like some sort of guided missle.
This is an old myth and is not true, the laws of physics will not allow it.
Sorry to burst some of you fella's bubbles,
Umm, how can I say this tactfully? This above post is the most incorrect, untrue, misinformed post I have seen since I have been visiting this site for 4 years and I am here to tell you I have seen some doosies. Posts like this is why I had to put the quote from Albert Einstein in my sig line. The fact that this post was posted in what I assume was all seriousness is almost beyond belief. Seems like every couple of months, someone somewhere gets on this site and starts up this debate over nothing. The facts are so well documented that it really makes the new guy look stupid for even debating this topic. Even the most unread armchair theorist in the world would have to, at some point in his life, stumble upon the research of this topic. And if not, here is just a sliver of some so you can no longer use ignorance as an excuse. Not to burst your bubble or anything but here she goes:
And I quote from Robert Rinker's book, Understanding firearm ballistics chapter 8 page 95 paragraph 4:
"[talking about gyroscopic stability]There are several methods of proving this is fact rather than theory. Of course, Gyroscopes have been studied in laboratories since at least the early 1800's. Bullet's flight paths have been examined extensively. ONe of the more modern methods is by special photographs and spark shadowgraphs, which show the attitude of the bullets as well as its place in space and time. THis is limited to only the best laboratories.
page 95 paragraph 7
Even a bullet that will quickly stabilize may leave the muzzle at a yaw as much as 5 degrees. Testing of .30 caliber match ammunition showed 4 nutations and .68 of a precession in the first 48 feet of the muzzle. That is typical. There are usually several nutations for each precession. The nutations are usually in the form of loops that pass through zero yaw. As we said earlier, this produces the path of a helix with flat spots.
page 96 paragraph 2
There will be a slight yaw and unbalance while the bullet is still in the bore. The confinement is relieved at the muzzle and the bullet departs in a slight yaw. This may be as small as a degree or two in a good barrel with the correct twist for the cartridge. Even a bullet that will become stable can have an initial yaw of up to 5 degrees. Yet a beginning yaw of as little as a degree or two can have a substantial influence. The yaw may be extremely high with the use of poor and mis-matched equipment. In any case, the force on the bullet is not on the bullet's center of gravity, but in front of it. As discussed, this force will try to tumble the bullet. The initial yaw outside the boreand the helix lead angle follows this interrelationship.
page 96 bottom paragraphs
The initial yaw as the bullet leaves the muzzle is governed mostly by stability. The direction of the yaw is haphazard or random and can be anywhere around the 360 degree of the muzzle. This makes target dispersion larger in cases of considerable yaw with low stability.
Penetration tests conducted by the U.S. army have shown less penetration at very short range than at moderate range. The lack of expected penetration at short range is blamed on initial yaw, which prevents the bullet from striking straight on. When the bullet stabilizes, the depth of penetration increases. Then the penetration gradually drops again as velocity, energy, and momentum decrease with extended range. The initial wobble that is yaw and precession can last up to 200 yards before settling down.
Page 98 bottom paragraph
Summary. To reiterate, yaw and nutation are different. Nutation is gyroscopic in origin and very small. Yaw is larger and while not cause by the same gyroscopic action, it still has gyroscopic relationship. Both are affected by precession and interact together. If the bullet is not moving through the air exactly point on, for whatever reason, then the pressure is not through the center of gravity but before or ahead of it. This creates an overturning or upsetting action, which because of precession has a result 90 degrees from where it is expected. Further, the high speed of rotation is constantly changing the direction of the upset, but always 90 degrees from the force.
Rinker than further goes into detail about spinning tops and has the math to show that they and aeronautic gyroscopes obey the same laws of physics as bullets and so on and so forth just as Dave Wilson was trying to explain.
Hope this clears it up again. I guess I need to just keep these pages on file so I don't have to keep typing this up the next time we get someone on here who doesn't know which end of the gun the bullet comes out of. Sorry for the grumpiness, I just get so damn tired of people trying to dispute the facts to confuse others who are trying to learn the science.