Subsonic vs Supersonic 9mm FMJ for self-defense

[CapnMac]

providing these calculations, for me, as a structural engineer,

And, that's the rub of it, the human body (in both general and in specific) "refuses" to conform to what ought to be obvious engineering distinctions of dimension and the like.

From Emergency Room doctors treating actual gunshot wounds, the distinctions "we" in the shooting community find significant are not so much noticed in the ER. So, a millimeter of round diameter makes almost no difference; neither does 4 or 5 meters per second (no matter how much our engineering minds might want to insist that it ought to). Human tissue is vastly elastic, and humans move around more than a little, too,

So the doctors can typically identify lesser or great than 8-9mm diameter and 25 m/s and under or 50 m/s and over in velocity. In engineering 5 meters/second (200fps) ought to be significant; in humans, not so much.

It's all too easy to get caught up in the minutiae. If a legitimate one in many ways. We need projectile weights and powder charges to be precise to very unforgiving standards.

 

[RadekSkylark]

@CapnMac, indeed a good point with regards to reports from ER, which is just another thing that points towards a conclusion that most probably reliability + accurate and fast hits is above all (at least in the realm of 9mm diameter bullets/rounds).

 

[CapnMac]

@CapnMac, indeed a good point

Not a problem, my intent is to serve the greater good. (Google suggests that scans as "Tā nav problēma, mans nolūks ir kalpot lielākam labumam" Latvian not being one of 'my' languages, sadly).

Also, that, as an Architect, I have similar problems as our brothers in Engineering, that we have to keep a grasp on the larger even as we are tightly holding on to the minute.

 

[RadekSkylark]

Not a problem, my intent is to serve the greater good. (Google suggests that scans as "Tā nav problēma, mans nolūks ir kalpot lielākam labumam" Latvian not being one of 'my' languages, sadly).

Also, that, as an Architect, I have similar problems as our brothers in Engineering, that we have to keep a grasp on the larger even as we are tightly holding on to the minute.

Oh yeah, it is indeed easy to sometimes get so concentrated on the small things while totally forgetting the larger picture.

As for the Latvian from Google, it is correct, although I'd have a hard time finding the "exact" words I would like to translate "the greater good" to, as "kalpot lielākam labumam" is not exactly a saying (in that wording) that Latvians use.

 

[golden]

RADEK,

I just saw an add for more of the non-expanding high velocity ammo. This time made by UNDERWOOD. It was on GUN BROKER. If you can access the UNDERWOOD AMMO site, it is a 90 grain non expanding bullet at 1550 fps for +P and 1400 fps for standard pressure ammo. I do not know if this "SCREW HEAD" ammo is more effective than a good hollow point, but it seems likely to be more effective than standard fjm ammo.

Jim

 

[CharlieFox42]

If I was restricted to FMJ, I'd go heavy. More mass will give you good penetration and reduce over penetration (although I'm sure I'll get push back from the experts here).

 

[Nuclear]

I was going to suggest a frangible round tip round, Norma has one at a very lightweight 65 grains, but someone shot a gel block and they zipped right through just like a heavier full metal jacket, so no advantage there.

 

[9mmepiphany]

More mass will give you good penetration and reduce over penetration (although I'm sure I'll get push back from the experts here).

Not an "expert" but I did some study in physics when in school.

Are you saying that the heavier mass will give superior penetration, but then loses that property when it encounters resistance?

In test I've taken part in, I've seen lighter bullets at higher velocity stop sooner...less penetration through water bottles/dry wall/gelatin...but just to opposite with heavier bullets. I'd be interested in which test you're basing your statement upon

 

[C-grunt]

Id buy the best quality ammo you can. FMJ 9mm is going to easily completely penetrate a person unless you hit heavy bone.

A rurncated cone profile does have a slight advantage over ball profile. The sharper from edge should cut a better wound channel and it should help reduce glancing off of bones. However we are getting into the minutia there.

If the turncated cone bullet is available in good ammo I'd go with that. But I'd go with quality ball ammo over a lower tier manufacturers turncated cone offering.

 

[Double Naught Spy]

More mass will give you good penetration and reduce over penetration (although I'm sure I'll get push back from the experts here).

I am with 9mmepiphany on this one. More mass will give you good penetration and yet magically be less likely to overpenetrate? How does it know when to stop?

 

[Gary A]

This thread in some ways reads like an argument for 9mm Kurz.

 

[Meeks36]

Using FMJ for defense, I suggest going with a flat nose bullet for straight line penetration. Round nose tend to deflect and wander more

When my pops was in law enforcement they had to carry round nose 38s. They called them Reggie pellets. Can’t remember the full story behind it. Something to do with how lethal hollow points are. This was early 80s in Atl suburbs.