Not all rifle rounds are created equal and neither are pistol rounds. But on average... the statement about velocity is true.
It is a combination of velocity, size, shape... Heavier bullets can do well at lower velocities, usually because they are larger diameter caliber. Flat bullets cavitate more than pointed... but there is a floor below which standard readily available bullets will not create large cavitation in relation to their size. This ratio of cavitation size to bullet size is important.
Even a golf ball will cavitate, and at relatively low velocities compared to a bullet. But that is in plain water, and penetration would be low.
Which is another problem... shallow cavitation. Which is what handgun hollow point rounds do. They expend most of their energy quickly in the first few inches, then its just direct displacement damage after that until it stops. And they can't just redesign to slow down the expansion rate, as then what little cavitation there is would be spread out and it wouldn't be as effective at causing pain.
22lr hyper velocity hollow points are another example, massive cavitation in relation to their size, but very shallow.
I would say the 1300fps mark may be close to the lower end of velocity that gives good cavitation across a good range of bullet shapes and types... 1300-1400fps seems about right, from the tests I have seen of the 22lr mini mags at 1200fps and velocitors at 1400fps. The difference between them is interesting.
Last edited by marine6680; September 23, 2012 at 01:16 AM.