Art S,

Cross caliber comparisons cannot be done using the SD of a bullet; its wrong, as it is a ratio that does not take into account the difference in momentum between the two scenarios that are to be compared. We need to recognize what force we put behind a given frontal area. Therefore, Mo/Xsa will give us a better indication when similar shaped bullets are being used. In addition, when different types of bullets are being used, we must also recognize that nose geometry will affect penetration dynamics further. When we introduce soft expanding bullets, a number of other factors kick in - loss of bullet weight, degree of expansion, rate of expansion, etc.

The value of SD lies in the same caliber when you have to make a decision as to what bullet weight you seek for a given application.

Let us not forget the superb historical performance of the smaller bore 404 Jeff (bore = .423") with a 400 gr bullet at 2150 fps, whereas today we generally load to 2250 fps with present-day powders. Furthermore, its reputation was built on FMJ RN bullets and not even on the much better present-day monometals with flat meplats. The SD of the above bullet happens to be .319 and the M0/Xsa = 719 [128.57/.1789]. If the same calculation is done with the .458 Win Mag (500 gr @ 1900 fps) then we get a Mo/Xsa of some 647, hence complaints of shallower penetration.

Chris

GS,
By volume, copper is heavier than steel.

did I just wake up in bizzaro world? Chris is a supporter of Mo/Xsa?

Gerard,
keep on making your great bullets
j

GS here are what my collection of 570gr Woodleigh SP driven at 2450+ fps look like. All have gone through a buffalo skulls from a head on perspective. None failed! All made it to at least the neck/shoulder junction.



Another view of the same bullets:



It is my humble opinion that the 619gr argument is nothing but an exercise in mental masterbation! 570 to 600 gr is plenty, and the 535gr pills worked DAMNED good too.

mrlexma
My experience was on Australian buffalo-both on the hoof and firing into just dead animals.This was from a 500 nitro at a chronographed 2120fps.

Wombat,

Just how did these Woodleighs fail you? You state over-expansion, did they only penetrate a few inches or was it that they did not exit after decimating the chest cavity? I haven't shot too much with them at the low velocities you site, but at higher velocity they worked well.

Thanks, wombat. That's what I was afraid of.

ScottS:
YOu are comparing apples and oranges. I'm talking about NE 500 ballistics, around 2100 fps, or even lower, and, you are talking about 2450 fps.

If a 570 grain bullet is the standard weight for penetration with a 500 NE, WHY WOULD ANYONE THINK THAT SAME WEIGHT BULLET, IN AN EXPANDING SOFT POINT, IS GOING TO PENETRATE EQUALLY? Doesn't make any sense.

I've got an idiot in another forum that thinks a 500 grain soft point, in .50 caliber, at 1800 fps is going to penetrate sufficently for cape buffalo, using the same logic.

These seems to be a pretty big issue with pistol rounds, and, sometimes, but less often, with rifle rounds.

GS