TexasTed

May 10, 2007, 05:19 PM

Is there a formula for calculating the striking force of a bullet. For instance, if I was trying to find out which gun delivered the most kenetic energy, how would I go about comparing a .44 mag. and a Casual .454? Granted, the powder and ball shape, size, and weight affect the comparison, but, I'm guessing now, for the max .44 charge and the max .454 one has got to be more powerful than the other? Is there a way to calculate this?

heypete

May 10, 2007, 05:30 PM

I generally use the projectile's momentum as a measurement of its striking force, after all, momentum is a measure of how difficult it is to stop a moving object.

Doing the math is simple: Simply multiply the weight by the velocity.

Thus, a 100 grain bullet moving at 1,000 feet per second has a momentum of 100,000 gr*ft/sec. A 200 grain bullet moving at the same speed has a momentum of 200,000 gr*ft/sec.

The numbers aren't terribly meaningful by themselves unless you're wanting to get into the physics of it all, but they make a good relative comparison.

For example:

9mm, 115gr bullet, 1,100 ft/sec has a momentum of 126,500 gr*ft/sec.

.45 ACP, 230gr bullet, 850 ft/sec has a momentum of 195,500 gr*ft/sec.

Thus, the 9mm has about 64% of the momentum of the .45, even though their muzzle energies are quite similar.

Now then, momentum may not be the deciding factor in how effective a cartridge is...for example, I could have a 30 pound (200,000 grains) object moving at 1 foot per second and produce 200,000 gr*ft/sec, but it'd hardly be effective in the same way that a faster moving, lighter bullet would be.

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