Just got done testing 36 grain Federal 'Copper Plated Hollow Point' ammunition (the 550 round box from Wal-Mart) in calibrated ballistic gelatin.
Shot one - penetrated to 16" in the block and was found on the ground, 4' behind the block. Average frontal diameter for all .22lr rounds tested was 0.28".
Shot two - penetrated to 14 5/8" in the block.
Shot three - penetrated to 15 5/8" in the block.
Shot four - penetrated four layers of light denim fabric and 14" into the block.
Shot five - penetrated four layers of light denim fabric and 14 9/16" into the block.
Shot six - penetrated four layers of light denim fabric and 12 1/2" into the block.
I did these tests not because I think the .22LR is a 'kick-butt defensive round', but rather to assess the defensive capability of a .22LR rifle, in this case, a Ruger 10-22. The only '.22' that I think I would choose in advance to use, would be a .223!
Shots seven and eight are special. They were fired from a .32ACP handgun with a 2.75" barrel (Kel-Tec P32). Previous tests of this round with (to avoid a flame war, no names will be mentioned) 60gr hollowpoints and the 65gr Hydrashok were conducted with good expansion but penetration distances far less than the accepted limit in gelatin of 12". As such, I went to work handloading 'special' loads for the .32ACP, taking advantage of the fact that the P32 is a modern handgun of Browning design. Just to give a 'sneek peek' of my next tests... One of them meets FBI standards for penetration and expands to about 0.50" . And the recoil is lovely too...
The block calibrated at 9.3cm and 575 ft/sec impact velocity.
Best wishes... Tom