The question asked was, "In a defensive rd for a handgun which is more important to consider....muzzle velocity or muzzle energy?"
At first glance, that seems nonsensical. Energy is a function of velocity and mass. But the discussion has flushed out more. Perhaps this will summarize things well enough:
The first one does not refer to bullseye accuracy; the target is likely to me moving fast, and the defender will not have time to aim accurately, or to reliably make one shot hit where he or she would like, and rapid repeat fire is likely to be needed.
Penetration into a given medium is a function of velocity, mass, diameter, bullet shape, and bullet construction. It can be measured by firing into surrogate materials that are generally representative of human targets. Predicting the results of that kind of tests using the results of penetration in water has been done.
There is not a lot of difference between the diameter of an expanded .45 bullet and that of an expanded 9MM bullet. A .45 will generally have a lower magazine capacity and, in a firearm of similar size and weight, greater recoil, which will make rapid repeat shots more difficult.
It hasn't been discussed much in this thread, but some may not realize that boom, blast, and fuss at the muzzle does not translate into "knockdown power." There's really no such thing.
There is insufficient information available, and there are far too many variables involved, for anyone to draw any meaningful conclusions from the results of real-world shooting incidents.
Personally, I do not see the point in spending much time trying to decide whether the modeled or tested performance of one particular round is marginally better than that of another. Given reasonable published assurances that all of my choices meet minimum standards (I'm happy with FBI standards), I will base my choices on reliability in my handgun, availability, and price, in that order.
At first glance, that seems nonsensical. Energy is a function of velocity and mass. But the discussion has flushed out more. Perhaps this will summarize things well enough:
- In handgun bullets, energy is not an imprtant factor in determining wounding effectiveness.
- The important factors are the following:
- Where the bullets hit, and in what direction, in a 3D human target
- Penetration
- Bullet diameter
The first one does not refer to bullseye accuracy; the target is likely to me moving fast, and the defender will not have time to aim accurately, or to reliably make one shot hit where he or she would like, and rapid repeat fire is likely to be needed.
Penetration into a given medium is a function of velocity, mass, diameter, bullet shape, and bullet construction. It can be measured by firing into surrogate materials that are generally representative of human targets. Predicting the results of that kind of tests using the results of penetration in water has been done.
There is not a lot of difference between the diameter of an expanded .45 bullet and that of an expanded 9MM bullet. A .45 will generally have a lower magazine capacity and, in a firearm of similar size and weight, greater recoil, which will make rapid repeat shots more difficult.
It hasn't been discussed much in this thread, but some may not realize that boom, blast, and fuss at the muzzle does not translate into "knockdown power." There's really no such thing.
There is insufficient information available, and there are far too many variables involved, for anyone to draw any meaningful conclusions from the results of real-world shooting incidents.
Personally, I do not see the point in spending much time trying to decide whether the modeled or tested performance of one particular round is marginally better than that of another. Given reasonable published assurances that all of my choices meet minimum standards (I'm happy with FBI standards), I will base my choices on reliability in my handgun, availability, and price, in that order.