# .40 can hit harder than .45 and .357 Magnum

buschmaster
Member Posts:

**14,230**✭✭✭
when can you say one cartridge hits as hard as another?

we can judge the power of a cartridge with kinetic energy and power factor. which one determines how hard a bullet hits?

if it has the same kinetic energy it might smack the target the same, but not have the power factor (momentum) to follow through.

if it has the same power factor (momentum) it might push as hard, but not have the kinetic energy to punch it like the other did.

it seems you can't pick only one.

so it stands to reason that, if it has the same kinetic energy

if it has more of both, then it hits

if it is equal to one, and has more of the other, that also hits harder.

well then....

.45ACP averages around 200 power factor and 360 ft-lb kinetic energy.

.357 Magnum has power factor in the upper 180's and kinetic energy in the low 600's.

when you look at the numbers for .40S&W and .357SIG

(BBTI data)

in a G22 they almost equal .357 (not much difference) and surpass .45ACP.

a G35 surpasses both of those. it hits

we can judge the power of a cartridge with kinetic energy and power factor. which one determines how hard a bullet hits?

if it has the same kinetic energy it might smack the target the same, but not have the power factor (momentum) to follow through.

if it has the same power factor (momentum) it might push as hard, but not have the kinetic energy to punch it like the other did.

it seems you can't pick only one.

so it stands to reason that, if it has the same kinetic energy

*and*power factor, then it hits as hard as the other.if it has more of both, then it hits

*harder*.if it is equal to one, and has more of the other, that also hits harder.

well then....

.45ACP averages around 200 power factor and 360 ft-lb kinetic energy.

.357 Magnum has power factor in the upper 180's and kinetic energy in the low 600's.

when you look at the numbers for .40S&W and .357SIG

(BBTI data)

in a G22 they almost equal .357 (not much difference) and surpass .45ACP.

a G35 surpasses both of those. it hits

*harder*no matter which way you cut it.
## Comments

15,437✭✭✭I can make in my garage right now a 9mm load that would make a 75 power factor and a 9mm load that would make a 175PF.

Power factor is simply Bullet weight x Bullet Speed.

https://www.dillonprecision.com/power-factor-calculator.html

15,200✭That might be the first time I've bothered checking the power factor of anything I've loaded. According to that link, my +P .45 Colt loads come in at a power factor of 350. :shock:

62,759✭✭✭✭http://ballisticsbytheinch.com/

48,547✭✭✭14,230✭✭✭but I don't want to go off on a tangent. too much explaining.

short answer: look at those PF's for 40 and 357SIG. same cartridge necked down. same PF's for the same barrel length. even though the .357 bullet is lighter. how is that? X amount of gunpowder = X amount of momentum.

mind blowing eh? you can use the exact same amount of gunpowder and get more KE because of more velocity due to the venturi effect, yet momentum remains the same. no free lunch in physics just expressing the energy differently.

but I 'm going off on a tangent.

1,003✭✭✭15,437✭✭✭12,889✭✭✭✭38,807✭✭✭51,001******It Will KEEL15,200✭14,230✭✭✭4,067✭✭✭14,230✭✭✭62,759✭✭✭✭