Plate to shoot - what to ask for at the hardware store

[Luckyorwhat]

Shot up mild steel from the scrapyard, no idea of the hardness but about 1/4" thickness was not challenging for any of the rifles we brought the other day, from SKS to Lee Enfield. Some interesting gouges from obtuse-angle hits, but not cool enough.

 

There are metal supermarkets were I am, but they didn't know what metal I'd want. I looked up some armour specs, but they seem to deal with lots of issues from welding to hardness. What do I ask for from hardware store guys if I want armour plate?

 

Also anyone have easy blueprints of test rigs they use? As of now we were using a bush and a hillside, but I'm thinking of upgrading to a PVC or 2x4 rig:)

[rmgill]

You want hard material. Thick and hard as possible to get. Mild steel tends to be ductile. What'll make it harder is the heat treating AND the chromium content. Certain quantities of nickel and carbon are good too but the key factor is a hardness that's rather higher than what you'll find in 'mild' steels. Something rolled will be tougher.

 

Anywhere from 300-600 Brinell hardness.

 

Bear in mind the really hard steels are rather brittle. Accounts from British factories in one or two of my books about making Armored cars state that the raw plates could shatter like glass if dropped. I guess the welding relieved them a bit.

[jwduquette1]

Shot up mild steel from the scrapyard, no idea of the hardness but about 1/4" thickness was not challenging for any of the rifles we brought the other day, from SKS to Lee Enfield. Some interesting gouges from obtuse-angle hits, but not cool enough.

 

There are metal supermarkets were I am, but they didn't know what metal I'd want. I looked up some armour specs, but they seem to deal with lots of issues from welding to hardness. What do I ask for from hardware store guys if I want armour plate?

 

Also anyone have easy blueprints of test rigs they use? As of now we were using a bush and a hillside, but I'm thinking of upgrading to a PVC or 2x4 rig:)

 

Hey Lucky:

 

Sounds like some very interesting experiments. We'd love to hear some more details.

 

Try looking through the following web page:

 

http://www.matweb.com/search/MaterialGroupSearch.aspx

 

Material properties for numerous steel types are detailed on the above web page -- mostly construction grade -- ductile, low hardness steel -- "mild steel". Look under the "ferrous Metals" subcatagory. Some Tool steels have the same sort of hardness levels as armor steel.

 

Portable hardness testers can sometimes be obtained cheaply from eBay. Depending upon the type of tester they can be reasonably accurate in determining hardness and tensile strength. Or; if you can get a sense for the actual steel type, it should be easy to figure out its various material properties.

 

Did you have an accurate gauge on the range to target? If you had an accurate range as well as an accurate muzzle velocity you can easily back-calculate the impact velocity for a given bullet.

 

Did you get an accurate measurement of obliquity? Magnetic Angle Locators are also pretty cheap.

 

How were you measuring plate thickness -- or multiple plate thickness?

 

Did you try the same bullets at the same range vs. sand bags or timber?

 

Any pictures?

 

Best Regards

Jeff

Edited December 30, 2007 by jwduquette1

[Luckyorwhat]

From this part of the forum I'd found a lot of details, ask for 4340 or 50, BHN anywhere from low 300's to high 600's, but is there a commercial name for armour plate that a clerk would recognize? I'm not sure if I used the word 'tempering steel' or not, I guess I'll phone again on Monday.

 

RGMILL yea that's the notion I got, I did search the steel thread here.l It's just I'm kind of ignorant, (though I've perused MATweb and learned what the basic tests and #'s mean), and talking to a store clerk it was like the blind leading the blind.

 

 

jwduquette1 It was actually a few thing combined... I think that's a good idea, I'll just have Matweb up and running and ask them what steels they have, and compare them on my end.

 

It was night, winter shooting, and that was just one of the targets. Range gauging is no problem, also got the Chrony. We enjoyed shooting holes in plates that it will probably become a staple.

 

There are pictures, but they're mostly of fireballs took on my buddie's camera. Plate shooting was cut short because 2 of us had already wrapped it up and were waiting in the car. My left foot was freezing every time I stopped moving, and the beers had turned to ice blocks. Camera batteries had died so no pictures yet, but as it's winter I don't expect too many people will put other holes in it (I just left it at the range, since I have other plates stll to bring out too).

 

One interesting phenomena to note is that the Lee Enfield holes could be distinguished from M14 holes, the .303 leaving a smooth edge around the crater and the 7.62x51 leaving a jagged edge with the jacket.

 

But still, it takes a LOT of steel to stop a rifle bullet and I wouldn't hide behind any, even at <45 angle bullets were making a mess on the back side.

 

The sand-bags idea is great, hand't thought of it and will test for sure now (need witness material now too). Timber, I may as well shoot gold bricks - can't believe the stuff grows on trees.

 

 

So yea it's time to get scientific, and start measuring properly. If I make a hanging rig to dangle the plates from, then it's OK to angle it toward the ground right? And just use a plumb-bob and level to measure obliquity?

[Marek Tucan]

Remids me of various tests from Box o' Truth

 

The Box o' Truth

[jwduquette1]

From this part of the forum I'd found a lot of details, ask for 4340 or 50, BHN anywhere from low 300's to high 600's, but is there a commercial name for armour plate that a clerk would recognize? I'm not sure if I used the word 'tempering steel' or not, I guess I'll phone again on Monday.

 

RGMILL yea that's the notion I got, I did search the steel thread here.l It's just I'm kind of ignorant, (though I've perused MATweb and learned what the basic tests and #'s mean), and talking to a store clerk it was like the blind leading the blind.

jwduquette1 It was actually a few thing combined... I think that's a good idea, I'll just have Matweb up and running and ask them what steels they have, and compare them on my end.

 

It was night, winter shooting, and that was just one of the targets. Range gauging is no problem, also got the Chrony. We enjoyed shooting holes in plates that it will probably become a staple.

 

There are pictures, but they're mostly of fireballs took on my buddie's camera. Plate shooting was cut short because 2 of us had already wrapped it up and were waiting in the car. My left foot was freezing every time I stopped moving, and the beers had turned to ice blocks. Camera batteries had died so no pictures yet, but as it's winter I don't expect too many people will put other holes in it (I just left it at the range, since I have other plates stll to bring out too).

 

One interesting phenomena to note is that the Lee Enfield holes could be distinguished from M14 holes, the .303 leaving a smooth edge around the crater and the 7.62x51 leaving a jagged edge with the jacket.

 

But still, it takes a LOT of steel to stop a rifle bullet and I wouldn't hide behind any, even at <45 angle bullets were making a mess on the back side.

 

The sand-bags idea is great, hand't thought of it and will test for sure now (need witness material now too). Timber, I may as well shoot gold bricks - can't believe the stuff grows on trees.

So yea it's time to get scientific, and start measuring properly. If I make a hanging rig to dangle the plates from, then it's OK to angle it toward the ground right? And just use a plumb-bob and level to measure obliquity?

 

You mean some sort of a framing system/buttressing setup something like this?

 

 

I assume you were firing lead or soft steel ball ammunition? The chronograph is a very nice touch for methodical testing.

 

As you indicated, typically thinner armor steel designed specifically for resistance to small arms or FSP is pretty hard plate. Most effective vs. small arms are face hardened plates; duel hardness plates; or High Hardness Plates such as ARMOX or the like. Duel hardness and face hardened plates will typically succeed in breaking-up matching or under-matching (sometimes even over-matching) uncapped projectiles before perforation -- ala ball or small arms caliber AP bullets.

 

Mil-Spec RHA isn't quite as effective as Duel Hardness plates or FH plate vs. small arms and needs to be in excess of ~12mm to be effective at stopping 0.30-cal M2 Armor Piercing at near muzzle velocity and 0-degrees obliquity. Mild steel\construction grade steel will of course be considerably less effective than Mil-Spec RHA at stopping bullets.

 

But it is still of interest to read about peoples experiences with methodical testing of various types of ball or AP bullets vs. common forms of "cover" -- ala mild steel, sand bags, concrete, brick, etc.

 

Best Regards

Jeff

Edited December 31, 2007 by jwduquette1