Doesn't seem too be much difference in penetration level. Nothing anyway that really puts one far ahead of the other.
They both still have similar penetration levels, and in my opinion- the soft lead .22lr bullets have more chances of tumbling/ deformation and fragmentation when shot in the human body.
To me thats more lethal than the thick copper jacket of the .25 acp that might make a slightly bigger hole- but more likely a straight hole/ and certainly won't deform or fragment.
There are many bones in the body that will stop/ deflect both .25acp and .22lr bullets at the 60 foot pound levels....However, if so- the .22lr will likely fragment or shatter upon impact with a dense bone, sending pieces in other directions. Wood isn't an accurate comparison to dense bone.
Think about how much more critical it would be for a surgeon to have to find where the bullet actually is in relation to angle of impact/ or if there are several pieces of the main projectile that have broken off and gone in other directions.
I've shot the .25acp- ...you literally have to be shooting at a boulder or steel plate to cause any deformation. This being solid point.
Last edited by m_liebst; January 17, 2013 at 10:25 PM.