[Sonic82]

For all you ballistic guys. What is more deadly at 25 yards, a .40 SW with a 3.9" barrel or a .357 leaving a 1.875" barrel? or is barrel length even that important?

[SSGN_Doc]

Too many more factors to consider and took many variables. Both can kill someone at that range so they could be considered equally deadly. A .22 can kill someone at that range so it could be considered equally deadly.

What do you really want to know?

[Colby]

If this is simply a ballistics question - energy at yards - it becomes a table look-up task.
But the table won't be even because you are comparing different barrel lengths and revolver to semi-auto. Revolvers have some pressure loss between the cylinder and the barrel.
Longer barrels contain the pressure longer - providing more power (energy/velocity) to the projectile. The very short 357 barrel will burn some of it's powder outside the barrel - losing some power for the projectile.

In practical terms... both would be deadly.

[austin92]

I'd guess the .357 would marginally carry more velocity and energy

[ScottA]

Reminds me of when someone asked what is the safest airplane.

The Piper Cub... it can only barely kill you.

[Colby]

Originally Posted by austin92

I'd guess the .357 would marginally carry more velocity and energy

Yeah.
The 357 mag has been considered kind of the standard for a powerful hand gun for many years - not considering the super powerful very large guns like 44 mag.

But I bet it would be close - between the 357 and the 40 cal out of the guns and barrels named.

[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.

[rjd3282]

The 40 can't compete with the 357 no matter what guns are used. The 40 simply can't match the power of the 357.

[Colby]

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.

[303tom]

Yes the .357 mag. would carry more velocity and energy....................