Further Comparison

.38 Super v .45 ACP.

What I gave here was a comparison of ball ammunition.

Who carries that anymore?

In GURPS terms for hollowpoints you up the damage type one step and add an armor divisor of 0.5.

So the .38 Super damage changes from 3d-1 pi to 3d-1(0.5) pi+.
.45 ACP changes from 2d pi+ to 2d(0.5) pi++

As I mentioned before pi+ increases damage that makes it through the armor by 50%, pi++ doubles it.

With an armor divisor of 0.5, they aren't punching much armor.  0.5 DOUBLES the DR of the armor and gives a DR of 1 against unarmored targets.

Average die rolls (3.5 per die) against someone in a t-shirt:

.38 Super lands 9 points raw, -1 for the "bonus" DR, so 8 penetrates plus 50% so 12 points of damage.  That's a major wound and a HT to remain conscious for the average person.

.45 ACP lands 7 points raw, -1 for the DR, 6 penetrates doubled gives 12...

Again they're nearly identical.

Neither will make it through that DR 6 vest on average, but the 38 Super has a chance.  Since that DR is doubled I need a roll of 13 damage or more to do any to the target.  Since the range of damage is 2-17, there's at least a chance of penetration.  Best roll, five will penetrate and be upped to 7 points of damage to the target.

What about 9mm you ask?

2d+2 pi becomes 2d+2(0.5) pi+.  9 on average, 8 gets through, 12.  Same situation as 38 Super with the armor.  Spread of 4-14...

I suppose I should be fair and add .40 S&W to the discussion.

.40 is 2d+2 pi+ for ball.  Unarmored target, average roll: 9, upped to 13 (I'm spotting a trend in handgun stopping power...)
Our DR 6 target: 9, 3 penetrates, 4 done.
Hollow points; 2d+2(0.5) pi++: 9, becomes 8, upped to 16!
Against DR 6, no penetration on average.  Range of 4-14, up to two could penetrate so there's a very small chance of getting 4 to the target.

Here's another view...  I'm often fascinated that a simple role playing game compares favorably with real world data.  Pic snagged from here: