Originally Posted by Sonic82
Maybe deadly was a poor choice of words. One or the other has more energy, mass and impact or whatever. If you substituted a .32 caliber for one of them it would be a easy question. No difference here except the two are closer...takes more mathematics. The gases leaving a revolver as mentioned is a relevant factor I would guess.
The ballistics tables are set up for measuring muzzle energy/velocity and energy/velocity at marked distances. This is measured stuff - straightforward to do this. But rounds are shot out of specified length guns - because barrel length does make a difference. Short barrels lose some energy.
As for the revolver cartridges - they are shot out of a revolver - so there are some pressure losses at the cylinder/barrel. So the measured energy out of the revolver includes the loss at the cylinder/barrel. The 357 mag is basically a revolver cartridge so the tables should reflect measured energy out of a revolver - with a certain barrel length.
The semi-auto - no loss there.
But the barrel length is a variable here. A 1 3/4 inch barrel is not the norm for testing. So the 357 energy out of that short a barrel would be somewhat less than a standard test barrel.
The 357 has been around a long time - I'm certain tests with short barrels vs long barrels has been done.
Google is your friend.