More scaremongering about centerfire .22's...

[jimmy the one]

19. the dancer undulates to the music

ezra: Cavitate is a verb; cavitation is a noun. To cavitate is to cause cavitation..

For something to cavitate is to cause cavitation - to itself. Cavitate is an *intransitive*verb as you are using it, where the verb does not apply to a direct object.

Cavitate: verb (intransitive) ...to form cavities or bubbles http://www.collinsdictionary.com/dictionary/english/cavitate
CAVITATE intransitive verb to form cavities or bubbles .. transitive verb to cavitate in http://www.merriam-webster.com/dictionary/cavitate

intransitive verb: a verb that indicates a complete action without being accompanied by a direct object, http://dictionary.reference.com/browse/intransitive+verb?r=66
intransitive verb: a verb (or verb construction) that does not take an object; http://www.freedictionary.org/?Query=intransitive%20verb

Undulate, shimmy, & cavitate are intransitive verbs, examples, parens added for clarity:

Valid: The dancer (herself) undulated to the music. Valid, No direct object.
Invalid: The dancer (herself) undulated the bucket of water. Bucket = dir obj.
Valid: The cat (itself) shimmied up a tree.
Invalid: The cat (itself) shimmied a tree. Tree = dir obj, tho it's commonly understood what is meant.

Valid: The gunshot victim cavitated after being shot by a hi speed bullet.
Valid: The ballistic gel cavitated after being shot by a hi speed bullet.
Invalid: The bullet cavitated the gunshot victim.
Invalid: The bullet cavitated the ballistic gel.
Invalid: The bullet cavitated causing cavitation in the victim/gel.
Valid: The bullet caused cavitation in the victim/gel.

Bullets do not cavitate, (unless they are mechanically affected which they cannot in less than a second), they cause cavitation due their mass, velocity, rotation or perhaps tumble.

I wrote: "The above defs mean 'to form' within a structure, or body in our case, I doubt the device used to form the cavity."
ezra: A rifle bullet impacts a deer, and a temporary cavity suddenly forms with its apex on the bullet, trailing behind the bullet for a foot or more. Hint: the bullet is the cause of the cavity.

Well of course, but that is not the bullet cavitating, it is the deer cavitating.
valid: The gunshot deer cavitated due to the speeding bullet.
Invalid: The speeding bullet cavitated the deer; the deer = dir obj.

You could validly write: The bullet cavitated in the deer - but that would mean the bullet itself suffered effects of cavitation while transiting the deer.

I wrote: This is actually not what is meant when referring to a bullet however, since bullet wise we are speaking of 'medical related' cavitation, not mechanically affected cavitation."
ezra: A bullet does not cause flow separation and temporary cavity mechanically? How else do you think it does it?

There is a diff between cavitation of metallic parts & cavitation used in wound ballistics. The cavitation noted below is NOT what we are concerned with. We are not in an engineering context discussing temporary wound cavities, we are in a medical context. That is what I meant in my sentence immediately above. Read the following para:
... Cavitation is a significant cause of wear in some engineering contexts. Collapsing voids that implode near to a metal surface cause cyclic stress through repeated implosion. This results in surface fatigue of the metal causing a type of wear also called "cavitation". The most common examples of this kind of wear are to pump impellers, and bends where a sudden change in the direction of liquid occurs. https://en.wikipedia.org/wiki/Cavitation

"If bullet hits bone or does not exit, collapsing tissue on the back end has no relevant affect on a bullet, it's a one trick pony & does not get shot again."
ezra: Yes. Your point?

Simply that the bullet does not undergo mechanical cavitation in either case, whether it exits or remains. It causes wounding cavitation, creating a cavity. -- Drying clay cavitated in the sun. Valid. The sun cavitated the clay, invalid. The Propeller cavitated in the churning sea, valid. The sea cavitated the propeller, invalid.

ezra: due to low-order cavitation and subsequent bubble collapse on the surface of the cavitating object, causing metal fatigue. That is irrelevant to very-high-speed objects like bullets.

I think he's got it. The propeller is cavitating. Tho ironically I think this valid: the propeller cavitates in the cavitating sea. Ha, combining both the mechanical with the general.

ezra: VALID: A propeller cavitates when the blade speed through the water is high enough to cause flow separation at that angle of attack.
ezra, INVALID: ..note particularly the temporary cavity formed by flow separation around the cavitating bullet..

I wrote: "If a bullet were to cavitate it would become pitted due to collapsing partial vacuums or impingements, irrelevant to this discussion."
ezra: ..no. The cavity a bullet causes is larger than the bullet, and the collapse occurs a foot or more behind the bullet.

No, the bullet itself does not form any cavity. The cavity formed is the tissue cavitating, not the bullet.
As I've said previous, 'cavitate' has morphed into being accepted as you are using it, bullet wise, tho I believe it is invalid usage.