100 grain .357 sig

Question
Is it true that the lower the wieght the better. I wonder this because the ballistics for the 100 grain .357 sig bullet are better than the 115 and 125 grain .357 sig bullet. If so, is a 100 grain .357 corbon bullet more strong than the mighty .45 super bullet?

Answer
Dave,

It's true that the lighter the weight the higher the foot lbs generated. For example, a typical .375 SIG with 125 grain bullet driven at 1450 fps will generate 584 ft/lbs. By contrast a 115 grain bullet driven at 1550 fps will generate 614 ft/lbs. .45 Super generates from 618-805 ft/lbs depending on bullet weight.

But foot pounds are a theoretical set of numbers that have a sketchy connection to the real world.  I don't really understand what you mean by "better."  "Better" for what?

Since my profile indicates self-defense, I'll assume that's what the realm you're looking for "better" in. "Better" will encompass a whole host of factors, including how easy it is to take rapid follow up shots (which is why the 10mm, which is a ballistic force to be reckoned with, has all but disappeared. The .45 Super is not a commercially viable cartridge for many of the same reasons).

Despite whatever the "theory" is, all calibers have a "magic bullet," an optimized bullet weight which, when driven at maximum allowable velocity, does "better" than bullets weighing more or less, "better" meaning producing more consistent incapacitation.

Since the .45 Super is not used by any police agency I know of (there may be one, but I don't know of it), it's actual street incapacitation factor is "zero."

A colleague of mine who is a theoretical ballistician takes the tack you mention - he believes that the lightest bullet driven at the fastest speed is most effective. The FBI, on the other hand, believes that the heaviest bullet, driven as fast as that heaviest bullet can be driven, is the most effective.

My study, though, has led me to the "magic bullet" theory for any given cartridge. In .40 S&W, that is a .155 grain bullet. Driven at maximum velocity is seems to produce more consistent incapacitation than that same caliber in 135, 165 or 185 projectile weight configuration.

In the .357 SIG, the 125 grain bullets seems to be its "magic bullet."

If, however, you want to define "better" as simply "what generates the most foot pounds?" - well, that's simply a matter of going to a ballistics table and looking up the answer.