<BLOCKQUOTE><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><HR> Those arguing that bullets cannot be tractable belong in the same room with the flat-earthers and those folks who say Apollo 11 landed somewhere in Nevada. <HR></BLOCKQUOTE>
I had quite an argument with one of these flat-earthers that finally got me kicked off that board. Apparently, I didn't pay proper respect to the resident guru in challenging his wisdom. (Actually, you've had a rather vicious run-in with the same correspondent.) Although he wouldn't provide any reference material to support his position, he assured me that 1) bullets remain fixed in attitude from muzzle to target; and, 2) I was out of my depth in trying to discuss the matter with him. He also said that the Ruprecht website was wrong and showed numerous errors and misunderstandings, but failed to give any specifics.
I'm glad to hear that your experience supports a result that seems to be intuitive even without the 1880 Army study or Ruprecht's math. I think that I can put this particular matter to rest.
I have Vaughn's book and have read through it but didn't find a specific reference to this issue. In his description of various trajectory topics, there is an assumption that the bullet noses over, but no specific discussion of the phenomena. In fact, one of things on my 2003 'to do' list is to track Vaughn down and engage him in conversation regarding this matter.
At any rate, thanks to all for the input. If anyone comes across any further information, either pro or con, please post it.
It is not only possible to cause instability due to overspinning it happens quite a bit. Not at the muzzle but many yards down range where the increase in SF causes a dramatic precession and yaw, which can lead to instability. At the muzzle there is insufficient different between bullet's angle of attack and flight path. Downrange, past the trajectory ordinate, there can be a significant difference.
I have radar data of bullets coming apart due to insufficient structural strength at high rotational velocities. I also have radar data of instability due to overspin down range. This is from the US Army's Yuma Proving Grounds last summer during a two day test which I ran. I spent many years working the formulas and talking theory and physics. Many of my questions were not convincingly answered. It is the test range with a good doppler radar that answered these questions. You can get meter by meter data and if set up right you can even see the spin of the bullet.
You can do it, too. A day's range time at Yuma only costs about $3500, and that includes the radar. It is the breakdown of the data that is expensive, because you have to do it yourself, and it takes time. The last shoot filled two CDs or about 1.2 gigabytes.
Simply put, your facts and theory are wrong. For one the GS, as you put it, continues to increase on the 147 gr. It is above 9.0 at 800 yds.
I have spent many years arguing the math and the theoretical with some very bright and experienced ballisticians, Bob McCoy being one. I recommend leaving the office and the computer programs and going to the range where a modern radar provides the solid answers.