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<bigcountry>
posted
I was playing with that bullet stabilzer program that ricciardelli has on his site. www.stevespages.com (Thanks by the way), and am having trouble understanding all the way. Do you want a bullet to overstabilized ever?

I was reading in American rifleman this month on stabilation, and they were using the formula T*L=150. Meaning twist is equal to 150/bullet length in calbers. Is this correct?

[ 01-03-2003, 20:03: Message edited by: bigcountry ]
 
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Picture of ricciardelli
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That's essentially the basic formula for the Greenhill factor.
 
Posts: 3282 | Location: Saint Marie, Montana | Registered: 22 May 2002Reply With Quote
<PaulS>
posted
Bigcountry,
Check your result with a Sierra 158 JHC bullet from a rifle at 2508 FPS with a 1:12 twist -
The software will tell you that the bullet is way over spun. My targets disagree 100%! I get .33 inch groups from my custom Remington with a Douglas barrel. When in doubt, more twist is better!

PaulS
 
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<bigcountry>
posted
Thanks, but that doesn't answer my question really. Any info would be appreciated.

Ricciardelli, that formula, is that the total length for the bullet? It really doesn't take into account if the bullet if flat nosed, or the wieght. Just looking for some knowledge. The program I got was from your website. Just trying to understand a little better.

[ 01-03-2003, 20:06: Message edited by: bigcountry ]
 
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Picture of Zero Drift
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bigcountry - if you really want to over analyze bullet configuration, velocity and proper barrel twist go to this site - http://www.lascruces.com/~jbm/ballistics/drag/drag.html

If you want to understand external ballistics go to this site - http://www.nennstiel-ruprecht.de/bullfly/index.htm

To answer your question - Yes, you can over stabilize a bullet. This is generally not a problem until you pass 150 to 200 yards. An over stabilize bullet will not allow the nose of the bullet to track the trajectory path. In other words, it will not nose over properly (like a football pass) and will maintain a nose high attitude to the target. When shooting LR (300 - 1,000 yards) you will find key holes in targets when bullets are over spun. In addition, over stabilize bullets do not �go to sleep� as quickly as properly spun bullets. This can cause additional accuracy problems.

Bullets do not act like drill bits - remember they only make one revolution per 9 to 14 inches of linear travel. There was some garbage circulated about over stabilized bullets penetrating better than properly spun bullets. This idea was based on observations from varmint hunters (where penetration is not a factor). They observed prairie rats exploding with greater force when bullets were over spun. This was later determined that the bullets were impacting the rat at an angle (nose high) causing frangible varmint style bullets to disintegrate quicker.

[ 01-03-2003, 20:31: Message edited by: Zero Drift ]
 
Posts: 10780 | Location: Test Tube | Registered: 27 February 2001Reply With Quote
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