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Suggested experiment: 9mm penetration of steel plate

11123 Views 4 Replies 3 Participants Last post by  applesmasher
Dear Sir,

First of all, I just want to say that I have immensely enjoyed trawling through your site and reading about the results of your experiments. This is exactly the sort of thing that I would get up to if I had a large selection of firearms and a place to use them. :)

There's one experiment that I was looking for in particular, but couldn't find.

I live in a rather dangerous part of the world (South Africa) and was looking to make up a set of diy body armour. Many people will jump in about now and say "get a real set of body armour" but there are two problems with that: (1) Cost and (2) most BO just protects chest and back, and I need something a little more extensive than that. We recently have some pretty violent strike action here (over, thank goodness) and it has become clear that body armour is going to become necessary, especially if I have to traipse to the factory at midnight to see why our alarm has gone off.

Now, my actual question is: what is the real world penetration of 9mm through mild steel plate?

And also: are several thinner plates as effective or more effective than one single plate of the same combined thickness as the thinner plates?

It seems to me that the most common (and dangerous) threat is the high velocity 9mm handgun round, and it would be great to know that x millimetres of mild steel are proof against a given round. (Yes I know mileage may vary depending on steel and load used.) Theoretical research I found elsewhere suggests as little as 2mm steel may stop a 9mm ... but then again, somewhere else somebody calculated a +p+ round could just about penetrate 5mm steel.

If you have the time and inclination, it would be of deep interest to myself (and others, I'm sure) to know what the outcome would be.

Thanking you kindly,
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Hi Bruno,

Glad that you enjoy the site.

Over the years I have had a number of folks ask me about shooting steel. But you have posted all the problems with such a shoot. The main one is that there are hundreds of different types of steel. And every one has different resistance to being shot.

The second is that different rounds will have different results.

All of those factors would mean that any such shoot would only tell us about one type of steel plate and one particular round. Not very helpful, as most of us do not have a lab to test and verify what the composition of our steel plate would be.

Because of these factors, I do not see such a shoot being very meaningful.

But thanks for the suggestion.
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Bruno, I have a few ideas which might help you.

First, I'd like to suggest that you obtain some mild steel of a sort which is available to you. If possible, ascertain the grade and record it.

Then test it yourself. I know that there is a shooting community in South Africa, so it might be a matter of finding someone who could put in some time to give you a hand.

Record the results photographically, and put them up on this forum. I would be delighted to see them myself.

Another thing to consider, while you experiment, would be steel in combination with other substances. For example, what happens if you bake a ceramic layer on top of, or beneath the steel? Or lead? Weight for weight, does it stop bullets better, or worse? What if you have a sprayed on plastic layer, such as is used to protect the beds of pickup trucks? What if you have a layer of leather on top of which and beneath which you have layers of steel platelets stitched on? Does the leather help to absorb the impact? What if it is fully tanned, but full grain leather? What if it is rawhide?

I don't know how the circumstances might require you to take your life in your hands, but I saw that many of the strikers were armed with cold steel. How well is a strike from a spear blocked?

Another option might be other metals. Various alloys might offer better options.

I hope that this gives you food for thought, and I am genuinely curious to hear what you got.
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Good day, gentlemen,

Thank you for the replies.

You are of course, correct, in that there is so much variation in steel grades and bullets that such a test would be somewhat pointless. :( However, I've since been scouring the depths of the internet and have come to the conclusion that around 3mm of steel should be sufficient to handle most 'regular' handgun rounds. If this is then backed up with say 4 layers of kevlar lining, I'd feel fairly confident that barring something high-velocity, it would stop most of the stuff out there.

I'm currently messing around, cutting plates to size, and will be constructing a jacket out of this, mainly to see if it's wearable and for size. If and when it is finished, I may well post a picture for your viewing pleasure.

The real steel to go for seems to be hard abrasion-resistant types, such as AR500. There may be a local equivalent. If this works out (and if I can come up with a viable method of dealing with bullet splatter / fragmentation) then maybe it would be worth making something out of such a high-grade steel.

A gun club is good advice. It is particularly hard to get a firearms license in South Africa, so most folks only have a single firearm. I envy Americans for having ready access to a plethora of goodies. :D A gun club would provide the variety of calibres necessary for such tests.

Anyway, thanks for the advice. I have greatly enjoyed your site, and the humour that went with the tests.

See you around later.
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I suspect that one of the strong points of the spray-on coating which is used on pickup truck beds is that it helps distribute impact over a wider area on the strike.

I have a sort of vision of a steel plate, coated in that stuff, then cut up and drilled to be stitched onto a kevlar or similar backing, in scales. It should be like a poor man's equivalent of that dragonskin bulletproof stuff.
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