Steel Shoot Results

[rucker]

Aren't the foot pounds calculations a little off?

Using your numbers the .45 should be 295 ft/lbs and the 9mm should be 309 ft/lbs.

Yeah, but it still doesn't "ring" true.

I'm really going out on a limb here but could it be because the slower (or larger, i'm not sure which matters) bullet reacts with the target for a longer amount of time than the smaller faster bullet? My physics class was at 8AM so I slept through most of them but it seems like that might be reasonable

edited to add:

Energy is transferred by work to an object or system when a force is exerted through a distance on that object or system. For a force to travel through a distance there has to be movement. Something has to move and push against something else. That something else that is pushed on is then also moved.

[JoeH]

A quick peek at a Federal ballistics chart shows that the .45 has more energy than the 9mm (muzzle, 25, 50, 75, 100).

The standard .45 has more punch than the 38 Soup +P at 25 yrds and out.

Enough with the fuzzy math.

[Pat]

Aren't the foot pounds calculations a little off?

Using your numbers the .45 should be 295 ft/lbs and the 9mm should be 309 ft/lbs.

Yeah, but it still doesn't "ring" true.

I'm really going out on a limb here but could it be because the slower (or larger, i'm not sure which matters) bullet reacts with the target for a longer amount of time than the smaller faster bullet? My physics class was at 8AM so I slept through most of them but it seems like that might be reasonable

edited to add:

Energy is transferred by work to an object or system when a force is exerted through a distance on that object or system. For a force to travel through a distance there has to be movement. Something has to move and push against something else. That something else that is pushed on is then also moved.

Given all of the above, the plates still seem to drop better with a .45 than with a 9mm. Still don't know why, though you may be right near close by mentioning the factor of time. Maybe more a factor of total energy consumed at target, i.e. ricochet effect vs. total energy absorbed.

I've read a whole bunch, but have never seen a real live answer to this question.

[hammAR]

I've read a whole bunch, but have never seen a real live answer to this question.

You should have been there Saturday, you would have seen a real live answer, well kinda.......

[rucker]

A quick peek at a Federal ballistics chart shows that the .45 has more energy than the 9mm (muzzle, 25, 50, 75, 100).

The standard .45 has more punch than the 38 Soup +P at 25 yrds and out.

Enough with the fuzzy math.

Federal is getting 890 fps for their .45 which works out to 404 ft/lbs.

We really need to know what everybody was shooting, escpecially macphisto.

For example:
WWB .45. 835fps and 230gr = 356 ft/lbs
Federal 9mm. 1180fps and 115gr = 355.48 ft/lbs

We should not have started down this road, it will lead to madness!

edit: I just realized though that most people with .45s were shooting with a 4" or 5" barrel while macphisto was shooting out of a 3" barrel......... <my head explodes>

edit2: It also makes a big difference where the popper was hit too. Too many variables, I give up! I'm just going to be happy that I have a .45 that makes big holes and knocks things down!

[EAJuggalo]

It was my 357Sig that scared the popper into falling sideways. 125gr at 1300fps, thats what the load is rated anyways. Maybe I should just put the .40 barrel in next time, see what that does.

[Jeff Bergquist]

Knocking down a popper is more of a momentum transfer than an energy transfer. Kinetic energy = mass x velocity squared as stated above, but momentum is just mass x velocity, making the velocity difference less important and thus giving the heavier .45 bullets the advantage.

[someone1980]

Knocking down a popper is more of a momentum transfer than an energy transfer. Kinetic energy = mass x velocity squared as stated above, but momentum is just mass x velocity, making the velocity difference less important and thus giving the heavier .45 bullets the advantage.

That is exactly what I was thinking too.

[Pinnacle]

IMHO

A larger mass moving more slowly spends more time on target (milliseconds) There is a measurement for this

It is called psi/ms - it is how we measure blast intensity and duration on target

a low velocity blast with a long wave duration (time on target) causes MUCH more damage than a short sharp blast

More time on target = more damage.

[joelr]

Knocking down a popper is more of a momentum transfer than an energy transfer. Kinetic energy = mass x velocity squared as stated above, but momentum is just mass x velocity, making the velocity difference less important and thus giving the heavier .45 bullets the advantage.

Close. It's 1/2 mv^2. For collisions, momentum analysis is probably a bit easier than energy analysis, and not just because the math's simpler-- for practical purposes, a collision between a bullet and a steel plate is going to be inelastic, and can be treated as a closed scalar system.

[Jeff Bergquist]

Close. It's 1/2 mv^2. For collisions, momentum analysis is probably a bit easier than energy analysis, and not just because the math's simpler-- for practical purposes, a collision between a bullet and a steel plate is going to be inelastic, and can be treated as a closed scalar system.

Duh, thanks for the correction. I should have said "is proportional to" instead of equals.