5.56 vs. auto glass test

[markm]

We happened upon a piece of what I think is auto glass this morning. So I took the opportunity to do some informal research that I had been promissing to do in another thread.

I used stuff that we found out at the range since I wasn't planning on doing this test today. The 3/4" plywood was used to tape my targets to so I could guage any deflection, and get an idea of what kind of penetration the round would have after it passed thru the glass.

Weapon used had a 14.5 inch barrel. I fired from about 7 yards away.

The first round tested was Federal NT frangible. The stuff that you can get from Ammoman.com.



The Frangible passed through the glass and appears to have broken into two main chunks that both penetrated the 3/4" plywood. No deflection at all.

[markm]

The second round is XM193. (second target taped to capture any deflection)



The M193 didn't appear to break. But it didn't pass through the backstop cleanly at all. It's the second exit hole in the board (on the right of the original 2 holes)
Looks like it keyholed to me.

[markm]

The 3rd round I tried was an M855 green tip. Once again, no deflection.



This round also failed to penetrate the board or the paper target cleanly. Another apparent keyhole. (it's the biggest gash in the center of the image, to the right of the first two exit hole clusters)

[markm]

The last round I tried was a .45 ACP ranger round. It penetrated the glass and the paper target cleanly. You can actually see the bullet hole in the paper. It's the nice round hole dead center of the MOA grid.

None of the rifle rounds on paper showed up very well in the images. It was hard to tell what I was getting with the camera because it was so bright out there. But none of the paper looked pretty where the rifle bullets impacted. Sloppy nasty keyholes. But all rifle rounds seemed to pass through the backstop with no deflection.

[CLHC]

Hey way to go!

So there's no deflection with the Frangible? Just curious to know and not that I'm in a position of any sorts to be shooting through automotive glass in a HRT or dangerous standoff, but what's the distance of your target from said glass?

[markm]

I'd GUESS the target is at least 2 feet behind the glass, but not more than 3 feet. I tried to simulate a head sized target at the average distance behind a windshield.

This glass wasn't angled very much.. maybe only 20 degrees off of vertical so It would stand up while being shot.

Unfortunately I didn't have any of the Federal Bonded ammo that I wanted to test.

[CLHC]

I'm wondering if one would put a dummy in a automotive seat and the glass in front to simulate a vehicle and then take a shot to see the "end" result? Of course maybe the test "subjects" could be from a junk yard.

[UVvis]

Was this tempered safety glass or laminated windshield glass?

Looks like fun!

[markm]

Was this tempered safety glass or laminated windshield glass?

Looks like fun!

I think laminated. Tempered would break into a bunch of tiny pieces wouldn't it?

It had no curve to it like a regular automobile windshield. It's almost like it was off of a bus or something with a flat piece of glass.

I have a profile shot of the glass that I can post later. It looked like two 1/8" pieces sandwiched together.

[Hootiewho]

Yea, that was laminated glass. Did you have the glass positioned straight up and down, or was it leaning at an angle like most car windsheilds? I have wanted to do some testing like that for a while, just for shits & giggles. I thought about calling some of the autoglass replacement companies and getting a few windshields to use. I imagine the angle at which the bullet hits the glass plays a big factor in deflection.

I have also wanted to make up some mock walls of sheetrock, insulation & other materials to see how well what rounds penetrate.

Good job, and nice write up.