Gyroscopic drift: Simplified?

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12-02-2009 | 11:57 AM

#11

driftrider

Nontypical Buck

Joined: Feb 2003

Posts: 3,802

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From: Coralville, IA. USA

Quote:

Originally Posted by CZ2506

Speaking of gyroscopic effect, a bullet leaves the muzzle at 3000fps. rate of twist 1:12. spin rate on the bullet is 180,000 rpm. At 400 yards, the bullet has slowed to 2000 fps. What is the rate of spin? I can't say this one keeps me up at night, but I have wondered about it. It seems like the surface tension Delta BC refers to would have slowed it down a little, but not as fast as "drag" slows down the bullet.

My understanding is that the bullets rotational velocity are reduced very little over the typical flight time of a bullet. For instance, a 150gr TSX fired at 3000fps will slow to 2000 fps at about 425 yards, which is just slightly more than 1/2 a second of flight time. I doubt it's even lost 5% of it's rotational velocity in that time.

Mike