Trying to identify bullet proof glass

[Monarch 10EE]

Does anyone know what this piece of bullet proof glass was in?
It’s always been around since I was a kid.
It’s 15” long, 7” wide, and 3” thick.
There are 13 pieces of glass in the laminations.
I’ve always thought it was military, not necessarily US, but it’s possible it’s not.

Thanks,
JW

[p-59a]

The only bullet proof glass I have ever seen are found on the front windshields of WW2 aircraft and they are configured in that shape. I have never seen them much more than an inch or so thick. Yours is not in that shape and is much thicker than that used on aircraft. That shape looks more like it was made for a building of some type. My guess would be some kind of blast proof building or maybe on a ship? Or it may have been made to test the ballistics of ammo being tested.

[Gary Cain]

As P-59 stated above, that is a size used for ballistics testing.

[Albert]

Do you live close to a life firing range? Could be a window from the hand grenade course....

[Monarch 10EE]

No firing range. It does look like it took a hit from something.

[srwestwood]

It might possibly be a vision block from a tank or armored vehicle. Look closely in the corners for markings. German tank vision blocks look similar except those that I've seen have thicker glass panes and less of them.