A while back, folks were discussing some low cost armor plates that were available on Ebay. I was intrigued at these 8x8 alloy steel plates for $40 so I got one for testing. Nothing scientific mind you, but I give it a worst case scenario test. Point blank hits by some powerful rifle rounds. All the shots were at a 90 degree face angle, so no "glancing" blow shots - these were all dead on hits.
First, I hit the plate with two 7.62x51 (.308) rounds from my FAL. These were 147gr British Radway from a 16" barrel FAL at 25 yards.
Upon inspecting the lack of damage to the plate, I skipped the rest of the FAL testing and moved to a .50 cal Beowulf. First two rounds were FMJ 334gr Ranier rounds and the third shot was a 334gr hollow point - all three at about 12 yards - literally point blank with roughly 2,600 ft/lbs of energy at that range.
As you can see by the photos, nothing penetrated. Needless to say, we were impressed.
I am in no way associated with the ebay seller, the manufacturer, or anyone who might profit or gain from the product. I just wanted to test the plates and am sharing it with the group here.