9mm and .38 special metal penetration

The Soviet WW2 SN-42 body armour consisted of 2mm steel plates, and 9mm bullets from couldn't penetrate it reliably at about 125 yards.

A 124 grain 9mm bullet has about 230 ft/lbs of energy at 125 yards, and something like 320 ft/lbs at 25 yards.

Let's make a calculation: (320/230*2mm)=2,8mm. So, a 9mm round should have trouble penetrating a 3mm steel plate at 25 yards. Of course, these calculations are most likely way off in every way.

From a more real life perspective, I remember shooting at an old car with a 9mm. The bullets could penetrate both doors easily, but left only a mark on a ~4mm reinforcing beam in the door if they hit it.

Tired_and_hungry said:

For the sake of real world accuracy in a short story that I am writing, what is the maximum thickness of medium carbon steel sheet which might be easily penetrated by the following rounds fired from a 4" barrel?

1) 158gr .38 special LRN @ standard velocity
2) 158gr .38 special FMJ @ standard velocity
3) 110gr .38 special silvertip hollowpoint @ standard velocity
4) 110gr .38 special bonded JHP @ standard velocity
5) 115gr 9mm JHP @ standard velocity
6) 115gr 9mm FMJ @ standard velocity

I fired a few 124gr non +P 9mm FMJs at a 2mm thick medium carbon steel plate at 24 yards and the rounds zipped through like a hot knife through butter. Since I can't get hold of thicker steel, has anyone here got any real world evidence of the metal penetrative capacity of the above rounds?

Click to expand...

Tired_and_hungry-

In Quantitative Ammunition Selection, there is a mild steel penetration model in chapter 8 that can be used to figure this out.


Taking your six examples and using the typical factory speeds for them (I added the manufacturer name), many being fired from 4" barrels, this is what I got using the sheet steel penetration model for the maximum penetration capability of each round:


1) 158gr .38 special LRN @ standard velocity (Remington: 755 fps) = 2.43mm
2) 158gr .38 special FMJ @ standard velocity (Fiocchi: 960 fps) = 3.63mm
3) 110gr .38 special silvertip hollowpoint @ standard velocity (Winchester: 945 fps) = 2.62mm
4) 110gr .38 special bonded JHP @ standard velocity (Federal: 1000 fps) = 2.87mm
5) 115gr 9mm JHP @ standard velocity (Federal: 1160 fps) = 3.88mm
6) 115gr 9mm FMJ @ standard velocity (Winchester: 1190 fps) = 4.05mm



Should give you an idea of what could be expected.

It seems in some circles, "standard velocity" would be NATO spec loaded. Lot's of people don't go on down to the malwart for ammo.

Certaindeaf said:

It seems in some circles, "standard velocity" would be NATO spec loaded. Lot's of people don't go on down to the malwart for ammo.

Click to expand...

Since none of the other loads that the OP mentions are of military/NATO issue, it appears that the OP is looking for U.S. commercial loads so I used those specs for all of the ammo.

The calculation for the maximum thickness of steel sheet that the NATO M882 (a 9mm 124 gr. FMJ @ 1299 fps) can defeat should be easy enough to complete.

^
I hear you.. however, NATO ball is "standard" for essentially the world.

The 2-3mm numbers sound about right. It's been a while, but I shot a bunch of sheet metal with various handgun rounds. If I remember correctly 10-12 gauge was the cutoff point.

Certaindeaf said:

^
I hear you.. however, NATO ball is "standard" for essentially the world.

Click to expand...

Well aware of that CD- I am sure that it is, but the OP was asking for 115 gr. FMJs, which while they are a STANAG weight, are less frequently encountered these days. I am sure that if the OP was looking for the M882 load he would have said so as he seems to be a pretty knowledgeable guy about this stuff given the language he uses in his questions.

I just wanted the author to be accurate in whatever he's writing is all. If our hero loads up with Winchester hardball, that's fine with me unless he's like in Turkey or somesuch for the most part.

So get on your fancy calculator and tell us metal penetration of NATO rounds already!

Oh CD, yeah, I'll do it for you just 'cause you asked.

Get it? O-C-D ?? ha ha ha

Here you go...

M882 (0.355", 124gr, 1299fps)- maximum mild steel penetration: 4.99mm

IMI Carbine Ball +P (0.355" 115gr, 1375fps)- maximum mild steel penetration: 5.15mm

lolz. cool

The BAT round goes more like 1600fps and is made of beryllium copper. I still have some.

Tired_and_hungry said:

To 481,

Could you help me calculate how much metal an 89gr 9mm JHP round travelling at 1280ft/s on impact could penetrate? I'm talking about the GECO BAT or Sintox Action 1 round.

Click to expand...

Sure...

According to the Schwartz mild steel sheet penetration model, a 9mm 89gr. JHP @ 1280fps should be able to penetrate a maximum thickness of 3.67mm of mild steel sheet.


The model is also able to calculate the "exit velocity" of rounds that exit less-than-maximum thicknesses of mild steel sheet, too, if that is of any interest to you.

I was about to say all should be able to penetrate 2mm of mild steel and I see the post "481" made bears that out.

Tired_and_hungry said:

To 481:

One last request, how penetrative would winchester's 85gr .380ACP silvertip hollowpoint be against steel sheets if the projectile impacts at 940ft/s?

Click to expand...

Sure.

Maximum penetration against mild steel sheet according to the Schwartz mild steel sheet penetration model would be 2.12mm.

The 85 gr. Silvertip would exit a 1.50mm thickness of mild steel sheet at 549.07 fps and a 2mm thickness of mild steel sheet at 247.92 fps.

Minimum required velocity (for the round in question) for penetration of a 1.50mm sheet is 762.97 fps; for a 2mm sheet it is 906.72 fps.

Back a very long time ago our dept had some Super Vel 38spcl +P armor piercing ammunition, I don't remember bullet weight/velocity or even why we had that ammunition.

Going back to another caliber designed to penetrate car doors, how does the 38 Super 130fmj/1300fps compare to today's FMJs?

Also, since I know 481 is itching to use his calculator, how does the Super rate with 147gr FMJs @1280fps?

FWIW, those interested in these types of bullet tests should look into getting the "Quantitative Ammunition Selection" book, it's written in a way that even I can understand. Best of all it's inexpensive and is available online. Once I learn how to use a calculator it'll even be better.

"Short story".

Perhaps.

2zulu1 said:

Back a very long time ago our dept had some Super Vel 38spcl +P armor piercing ammunition, I don't remember bullet weight/velocity or even why we had that ammunition.

Going back to another caliber designed to penetrate car doors, how does the 38 Super 130fmj/1300fps compare to today's FMJs?

Also, since I know 481 is itching to use his calculator, how does the Super rate with 147gr FMJs @1280fps?

FWIW, those interested in these types of bullet tests should look into getting the "Quantitative Ammunition Selection" book, it's written in a way that even I can understand. Best of all it's inexpensive and is available online. Once I learn how to use a calculator it'll even be better.

Click to expand...

Today's car doors, if they are made of metal to begin with, usually consist of an exterior sheet of 20 ga CRS -mild steel- about 1mm in thickness. Unless a bullet meets with a structural member or something like an electric window drive motor, it'll pass through retaining much of its velocity.

Using the Schwartz metal barrier penetration model, the two examples that you specify work out like this-

.38 Super 130gr FMJ @ 1300fps

Maximum CRS Penetration: 5.20mm

Exit Velocity after 1mm of CRS: 1206.66fps


.38 Super 147gr FMJ @1280fps

Maximum CRS Penetration: 5.61mm

Exit Velocity after 1mm of CRS: 1196.44fps


Using these exit velocities in the Schwartz bullet penetration model (the one for gelatin and soft tissue) after they pass through 1mm of CRS, the .38 Super 130gr FMJ is capable of producing 30.47 inches of penetration and the 147gr FMJ is capable of producing 35.64 inches of penetration in gelatin/soft tissue.


Needless to say, car doors are not cover.