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From: (Bart Bobbitt)
Subject: Re: Does anyone sell a bullet spinner?
Organization: Hewlett-Packard Fort Collins Site

russell.nixon ( wrote:

: ......... don't bullets spin at
: ~100k rpm?

Yes; in .22 centerfires, near 3 times that fast.

:  If so, a Dremel will only spin a chuck at ~25k rpm.  Would
: the slower speed be a valid test of the bullet's dynamic characteristics?

Yes.  In the early 1970s, someone made a precision fixed-jaw chuck to
fit in the Dremel tool.  It was drilled out with one of the cherrys used
by Sierra to make their bullet pointing die for match bullets.  Bullets
spun in it at about 30,000 RPM did one of two things:

  * The well-balanced ones spun perfectly.  No wobbling of the chuck
    was noticed.  From a machine rested match rifle, 600-yard groups
    were in the order of 1 to 2 inches; twenty-shot groups at that.

  * Those with unbalance enough to cause the chuck to wobble just a tiny
    bit shot 4 to 5 inch groups at the same range.  Some of 'em were so
    unbalanced, they flew out of the chuck and bounced around the room.
    Seems there was no need to pick up those that flew out; they weren't
    worth finding and shooting in the first place.


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