Light fast or slow heavy for steel?

[JLB-US]

Sure this is around here somewhere but my "Search Fu" is weak tonight

Assuming the exact same power factor, is there any difference in steel dropping between light and fast, or heavy and slow loads, on less than optimal hits?

[Sarge]

Some say yes and some say no. All kinds of theories and "facts" swirling around this one. In my own personal experience Good loads at about 130+ PF will all knock steel down just about the same. Remember, calibration ammo is only around 120 PF so.......

[flyingchipmunk]

This is mere speculation, but it would seem that lighter and faster would work better. Knocking over steel requires energy and energy is mass times velocity squared (E=MV^2). Power factor on the other hand is simply mass times velocity (Pf=MV). Therefore you get more energy out of a round that is going faster because velocity is squared and therefore much more important to the energy equation.

On the other hand as Sarge pointed out, the steel is all calibrated to fall with minor power factor ammo. Hitting the steel solidly is much more important than the small difference lighter faster bullets might make. So shoot whatever you, and your gun, shoot well

[flyingchipmunk]

double posted

Edited September 22, 2014 by flyingchipmunk

[Matt in TN]

This is mere speculation, but it would seem that lighter and faster would work better. Knocking over steel requires energy and energy is mass times velocity squared (E=MV^2). Power factor on the other hand is simply mass times velocity (Pf=MV). Therefore you get more energy out of a round that is going faster because velocity is squared and therefore much more important to the energy equation.

On the other hand as Sarge pointed out, the steel is all calibrated to fall with minor power factor ammo. Hitting the steel solidly is much more important than the small difference lighter faster bullets might make. So shoot whatever you, and your gun, shoot well

In a collision (what happens when a bullet impacts a plate), only momentum (p=m*v) is conserved between the two bodies. Energy is conserved within the SYSTEM, but a very good portion of it is lost to heat, sound, light, etc. it is true that kinetic energy (energy of the moving bullet) is equal to mass time the square of velocity, but it won't all go into the plate so it really doesn't matter much here.

Of course as already mentioned, they'll all fall if you hit PF=130.

[Aglifter]

Pf, correlates to inertia which is just about momentum and impulse in this situation.

The only real difference might be that a heavier/stronger bullet, at slower speed seems to transfer more of that momentum to the plate, and spend less on fragments flying everywhere.

[zhunter]

I'm a believer in heavier slower bullets for steel. The bullet impact is slightly longer, a heavier longer impact just seems better.

Of course we are only talking about minor loads, major loads are not an issue

[bigarm]

I have no idea, but i can tell you that my wife's 45 is impressive on steel. A lot of people comment on it when she is shooting.

[Sarge]

I have no idea, but i can tell you that my wife's 45 is impressive on steel. A lot of people comment on it when she is shooting.

Probably shooting MAJOR PF right? a 9MAJOR or 38 super shooting a hyperactive 115 grain bullet are pretty impressive as well!

[bigarm]

I have no idea, but i can tell you that my wife's 45 is impressive on steel. A lot of people comment on it when she is shooting.

Probably shooting MAJOR PF right? a 9MAJOR or 38 super shooting a hyperactive 115 grain bullet are pretty impressive as well!

Yes she is. It makes my major power factor 40 look like a pea shooter.

[eric4069]

I'm a believer in heavier slower bullets for steel. The bullet impact is slightly longer, a heavier longer impact just seems better.

Of course we are only talking about minor loads, major loads are not an issue

for Production 9mm minor my impression from my own shooting is that 147 grain takes down steel better than 115 grain at the same power factor.

Eric

[rdinga]

I am of the heavy bullet moving slow school of thought. Even though in the presence of witnesses I have hit plates with a 9mm using 147's and the steel just stood there and smiled at me.....

[kneelingatlas]

a 9MAJOR or 38 super shooting a hyperactive 115 grain bullet are pretty impressive as well!

I shot a match once in Open minor using 100gr bullets at ~150pf, I was worried about steel, but they dropped like a rock!

[steviesterno]

i really wish we could come up with some real data on this some how. If fast and light was the most powerful, wouldn't all HD/CCW handguns be 5.7 or something like that instead of 45?

For 3 gun I use the heaviest 223 gn I can get for steel stages or flashers, since it "whaps" them down with more umph than 55gn. That's as scientific as I can get about that. hit a popper with 223 and then again with 308 and see which does more good.

I wish I knew. All the speculation has me building a 300BLK rifle since 220gn at under the speed of sound is like a 45, and I do like the 45s. Makes the steel fly with major PF

[IDescribe]

If the same power factor, the slower bullet has more dwell time on the target and builds more momentum in the target before rebounding. Whether or not it's enough to make a difference...

As to wishing there's a way to test it, there is. Build a bunch of 9mm ammo with both super light 95 grain lead RN bullets and 160 grain lead RN bullets. Build them all at the same power factor, let's say PF 130. Calibrate a popper to fall inconsistently, as in NOT consistently, with the 95 grain bullets, let's say the popper falls about half of the time. Then switch to the 160 grain bullets at the same power factor. Does the popper fall more often? Yes? Then heavier and slower is better. Less often? Then faster and lighter is better (not going to be the case). Does it seem to fall neither more nor less often? Then it's either or wash or not different enough to matter. Easy test. Someone mail me a popper. Or search long enough to find the thread where someone has already done that and posted the results. I find it hard to believe no one has tested that before.

[zhunter]

A .45 has always appeared to knock steel down better than a .40, wouldn't that be a similar test that most of us have seen previously?

[IDescribe]

A .45 has always appeared to knock steel down better than a .40, wouldn't that be a similar test that most of us have seen previously?

It would have to be at the same power factor to mean anything in terms of the OP's question. I was trying to go as apples to apples as possible: same caliber, both lead, etc.. I can only imagine that there are some minor differences between jacketed and lead bullets, as well.