A brief graphical analysis of the 9mm 115 gr. FMJRN and the .45ACP 230 gr. FMJRN

[481]

It seems that one of the perennial topics on internet gun forums is the comparison of the 9mm and .45ACP using ball ammunition.

Using the Schwartz terminal ballistic model to analyze the maximum penetration depths and the corresponding mass within the permanent wound cavities of the 9mm 115 gr FMJRN and the .45ACP 230 gr FMJRN across a wide range of velocities (200 fps - 1600 fps), I thought that graphs might be a visually-informative way to illustrate the data for those who might be interested in it.

Since a bullet that lacks the velocity necessary to penetrate skin will fail to penetrate a human body, it was necessary to determine the lower velocity limit to be used in the analysis.

For this task, I used the skin penetration model found in the research paper below-

http://www.dtic.mil/ndia/2005garm/tuesday/hudgins.pdf

-to determine the minimum velocity at which both the 9mm and .45ACP FMJRNs would successfully penetrate human skin of average thickness (~3mm). Those values are 194.5 fps for the 9mm 115 gr FMJRN and 179.4 fps for the .45ACP FMJRN.

Since either round must have a minimum velocity of less than 200 fps to pass successfully through human skin, 200 fps was used for both rounds as the lower limit for the analysis.



This graph illustrates the maximum penetration depths (in inches) of the 9mm 115 gr FMJRN and the .45ACP FMJRN at impact velocities of 200 fps to 1600 fps-





This graph illustrates the mass (in grams) of permanently crushed soft tissue within the entire volume of the permanent cavity of the 9mm 115 gr FMJRN and the .45ACP FMJRN at impact velocities of 200 fps to 1600 fps-




Using a manufacturer's ballistic table to determine the velocity of the FMJRN at a desired range, the maximum terminal penetration and the amount of permanently crushed soft-tissue within the permanent cavity can be found using the charts above.

One of the most startling implications of this analysis (at least to me) is the amount of penetration that both rounds would produce even at extended ranges where velocities are well below 400 fps.

[seeker_two]

Interesting......what does it mean?

[Nanuk]

Doesn't an FMJ tend to slip through vs crush tissue?

[bacardisteve]

Yes FMJ wont cause as much trauma as a hollowpoint...if the hollowpoimt works as designed which isnt always the case.

[nate45]

Originally Posted by seeker_two

Interesting......what does it mean?

It means that chunks of metal, even relatively small chunks of metal, flying through the air at anywhere from 270 to 800+ miles per hour, have the potential to cause a wound in flesh and bone.

We're going to have to rethink everything now. This could possibly be one of the causes of deaths and injuries, in for instance World War II. Someone should definitely look into it.

[seeker_two]

nate45: Good point.....because, if bullet wounds didn't cause death in WWII, we have a lot of digging up to do....

[481]

Originally Posted by Nanuk:

Doesn't an FMJ tend to slip through vs crush tissue?

For the most part, yes. However, FMJs do damage a very small amount of tissue as they pass through it.

For example, the charts indicate that a 9mm 115 gr FMJRN @ 1100 fps would penetrate to depth of ~26 inches and crush ~30 grams of tissue over that entire distance.

Dividing the total mass within the crush cavity (30 g) over the entire length of the wound channel (26") gives a value of 1.16 grams of tissue crushed for every inch of the bullet's travel. That is a very small amount of tissue that would weigh about 18 grains.

For a perspective of just how small that really is, imagine cutting a .223 55 gr bullet into three pieces. Each of the three pieces would weigh about 18 grains- that is how much tissue is crushed for every inch that the 9mm 115 gr FMJ travels.

[RC20]

Charts are not real world.

You want to know effective get real world statistics.

[Officer's Match]

What I'm seeing is that at 700fps the 230gr 45 crushes roughly twice as much tissue as the 115gr 9mm. However, that is handicapping in favor of the 45, since the 9mm is likely to be traveling more like 1000fps on impact, at which speed it is crushing 2/3 as much tissue.

So, what remains is there is still room to disagree. If only one shot will hit, make mine a 45 (out of those two). However my "plan" would not likely involve one shot if (God forbid) required to exercise said plan.

[nate45]

If only one shot will hit, make mine a 45

If that one shot hits in the same exact spot, a 9mm through the heart, major artery/vein, spine, brain beats a .45 that misses those vital areas.

Both the 115 grain 9mm Luger and the 230 grain .45 ACP have more than sufficient penetration to reach the vitals. The slight wounding advantage of the .45 ACP, is of minor importance.

Bottom line is, they both fall into the classification of service cartridges, that is to say ones that are suited for Military and Police Duty. Either one does an okay job in that role. Whether the projectiles be FMJ, or expanding.

[Officer's Match]

Agreed Nate, just parsing the info for theoretical purposes. The capacity argument is a good one and very compelling. What isn't always pointed out is that it isn't a given one will be able to effectively employ the additional rounds - sometimes (unfortunately) the best one can do is land one good shot.

Now, my controversial opinion: I remain unconvinced that the impact energy (oh no, the dreaded "knockdown power") is never of any significance. Maybe it never is, but when I look at the difference on steel or pins, I still can't ignore it. That said, do I think the 9mm is effective? You betcha'.

[nate45]

Don't get me wrong, I was just expounding on your point really. There is no question that the 230 grain .45 ACP packs more momentum and does more damage than the 115 grain 9mm Parabellum. Given equal placement. It would be the one I would prefer too, in a one shot affair.

On the spectrum of pistol cartridges, that are classified as service cartridges, the 9mm is on the bottom rung. That is to say, it defines the lower margin of acceptability. Acceptable, is acceptable though in a go, no go test and the 9mm Parabellum is an adequately preforming Military and Police cartridge, no question.

[seeker_two]

Originally Posted by nate45

On the spectrum of pistol cartridges, that are classified as service cartridges, the 9mm is on the bottom rung. That is to say, it defines the lower margin of acceptability. Acceptable, is acceptable though in a go, no go test and the 9mm Parabellum is an adequately preforming Military and Police cartridge, no question.

If we're talking service cartridges, any way one of those could be done for the .38SPL SWC round?

[Josh17]

I thought the 9mm had MORE velocity and MORE penetration vs a 45ACP while the .45 ACP had less velocity but would cause a bigger hole in the target. This chart seems inaccurate. Isn't the 9mm vs 45acp the whole "small, fast moving bullet vs the slow, bigger bullet"??? That's what I've read everywhere.. 9mm is small, but fast moving and tends to over penetrate but cause less of a "big impact hole".

Then again it is just a chart. I could probably look up another chart as find opposite results. Every chart has their different "stats".....

[JohnKSa]

This chart seems inaccurate.

You need to compare the chart curves using typical velocities for each caliber.

If you do that, you will see that a 115gr 9mm FMJ bullet travelling between 1100 and 1200fps will penetrate about the same amount as a 230gr .45 FMJ bullet travelling between 800 and 900fps--that is, about 2 feet.

That's good because that's pretty much what ballistic gel testing says.

What I'm seeing is that at 700fps the 230gr 45 crushes roughly twice as much tissue as the 115gr 9mm.

It's important to keep track of the scale of the damage. At typical velocities, one destroys about 1.7oz of tissue, the other about 1.1oz of tissue. It becomes very clear how important it is to put the bullet in the right place. Destroying an extra half ounce of non-essential tissue won't make any practical difference at all.

[481]

Originally Posted by JohnKSa:

It's important to keep track of the scale of the damage. At typical velocities, one destroys about 1.7oz of tissue, the other about 1.1oz of tissue. It becomes very clear how important it is to put the bullet in the right place. Destroying an extra half ounce of non-essential tissue won't make any practical difference at all.

Great post.

I've never thought of it in quite that way. Extremely insightful.

[Nanuk]

It's important to keep track of the scale of the damage. At typical velocities, one destroys about 1.7oz of tissue, the other about 1.1oz of tissue. It becomes very clear how important it is to put the bullet in the right place. Destroying an extra half ounce of non-essential tissue won't make any practical difference at all.

That is only if the full caliber width is damaged, the FMJ notoriously does little damage as it slips through, hence the deep penetration.

This thread is a waste of good bandwidth.

[Double Naught Spy]

It's important to keep track of the scale of the damage. At typical velocities, one destroys about 1.7oz of tissue, the other about 1.1oz of tissue. It becomes very clear how important it is to put the bullet in the right place. Destroying an extra half ounce of non-essential tissue won't make any practical difference at all.

Right, given equal penetration, you can't expect double damage without double area (bullet diameter) and so as John KSa noted. After all, the .45 acp is only about 1.6 times large (frontal area cross section) than 9mm.

With that said, the amount of tissue destroyed may not be as relevant as the amount of tissue damaged. You don't have to destroy an artery to cause severe bleeding, but simply lacerate it. A laceration will actually destroy very little tissue, but can seriously compromise the function of the vessel.

As noted, destroying (or lacerating) non-essential tissue won't make any practical difference.

[481]

Originally Posted by Nanuk:

This thread is a waste of good bandwidth.

I am sure that the Mods would've shut this thread down if that was the case.

[manta49]

That is only if the full caliber width is damaged, the FMJ notoriously does little damage as it slips through, hence the deep penetration

You would wonder how the military manage with 9MM FMJ. PS I know they have to use FMJ.

[Xfire68]

That is a very small amount of tissue that would weigh about 18 grains.

Yes that is but, I guess it would depend on what 18g of tissue it was crushing? Brain tissue, Heart Tissue?

[481]

Yes, I agree.

"How much" and "what kind" are very important, indeed.

[militant]

Its where not what.

[bacardisteve]

The military only carry fmj oconus. Stateside we carry hollow points or atleast they did up untill 2010 when I seperated. We were also trained to use the "mozambique" drill with our m9's. That is two to the chest one in the head we even had to shoot that way for qualifications.

[phred119]

Curious as to why you compared the lightest 9mm (115gr) with the heaviest 45 (230gr)?