Wednesday, April 2, 2008

3/4" Thick Steel Vs. .308 Win

I now have a 3/4" thick piece of steel ready for testing:




Do you think this will be able to stand up to a .308?



Those of you who are up to date on your physics and calculus can just do a little math and figure out what will happen.

Here is the data required for the calculation:

The steel plate in question is actually 3 pieces of 1/4" thick ASTM A36 welded together.
The mechanical properties of which are:
Yield Strength: 248 MPa
Tensile Strength: 400 MPa
Young's Modulus 200 GPa
Shear Modulus 70 GPa
Poisson's Ratio 0.26
Density 7861 kg/(m^3)

The bullet specs are:
Composition: Copper jacketed lead
Weight: 150 grains
Velocity @ 100 yards: 2533 fps
Energy @ 100 yards: 2137 ft-lbs

I posted all these numbers because I'm sure that Ben will be able to determine precisely what the outcome will be.

I could do the math too...if I wanted to...but I don't want to spoil the surprise.

What do you think will happen when I shoot it?
Will it:
-Bounce off leaving the plate unscathed.
-Make a dent but fail to penetrate.
-Punch right through.
-or something else?


...shooting stuff is fun.

6 comments:

  1. I quickly did the math in my head and determined that it will make a dent but not penetrate all the way through.

    The data you included is incomplete in that it doesn't take weather into effect. I assume the experiment will be done in the next few days and I happen to know we're due for a little foul weather. If I'm correct on where this experiment will take place, you'll be shooting toward the west and therefore into what I predict to be a 15mph headwind. While that definitely won't do much to a speeding bullett, the numbers pencil out to be SO close that the head wind WILL keep the bullett from full penetration.

    Of course you won't be able to actually see that becuase the scope of your rifle will be embedded into the flesh just above youe eye.

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  2. Max, are you certain that the projectile will not bounce off the steel and come back and hit you or someone else???? I am concerned.

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  3. Benny, I will actually be shooting at about S 3° E.

    And shooting from an elevation of 1214 feet to a target elevation of 1199 feet.

    Could you recalculate using this new information and see if you get a different result.

    Thanks.

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  4. Don't worry Mel. Lead doesn't really bounce off steel. I sort of 'splashes' and it definitely won't come back 100 yards to get me.

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  5. That does make me feel a bit better, but be careful anyway!

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  6. Why didn't you tell me you were shooting downhill?

    Given the new information, I'd say to plan on a clean bullett hole all the way through.

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