Shooting cows has about as much to do with self defense as shooting cinder blocks.
The Myth of the hollow points effective stopping power is jus that a myth. In actual shooting incidents and autopsy reports, half of the time in all observed caliburs hollow points fail to open. It is generally observed that they either flatten and turn sideways or the cavity is filled with the subjects clothing turning the bullet into a lightwieght hard ball.
Having said that, the US military has done 3 scientific studies on bullet design wieghts and loadings. Using naked, clothed and behind various kinds of cover cadavors. IE dead human bodies.
The results of the first 2 studies were the same, heavy hard ball ammo is the most effective pistol ammunition fr penetrating clothing, bone, cover etc, and still having the energy to damage vital organs.
The result of the first test caused the US army to adopt the .45acp and the Brittish to adopt a 200 grain .38 special in a revolver. Both loads were excelent in combat, but as it turned out the .45 acp was preferred. The second test done before ww2 had the same results, heavy slow bullets, .45 .44 etc. The us kept te .45 acp.
The third test was done in the early 90's, its results havenot been made public. Having said that, it is interesting that US law enforcement agencys have been adopting the .357 sig, slowly replqacing the .40 sw
I believe this is being done because of the prevelence of women in law enforcement, who generally do not posses the upper body strenght to control a heavier bullet. The .357 sig is an attempt to replicate heavier bullet performance with a lighter fater bullet to reduce recoil.
Having said all that, the best calibur for personal defense, is the largest calibur you can personally control shot out of a gun you are likely to carry with you.
But the real science is in andhas been for over 100 years, heavy slow harball ammo is the best for killing humans with a pistol. Anything less is a compromise, which is fine as long as you know its a compromise.
One other thing which is as sure as Obama is a commie, hard ball ammo is more effective at killing humans than any hollowpoint yet devised. Hollow points are desighned to limit penetration, which they do. But to kill somebody you need penetration, determined human attackers are stoped only two ways in a gun fight,
Disruption of thespinal column
Or
Bleed out
In either case only adequate pennetration accomplishes these goals.