Well, my two cases of SOCOM 5.56 "Optomized" 70gr "Brown Tip" came in today. Tested it against a cinderblock and against water/paper/water.
Cinderblock showed penetration through both sides, with VERY little energy remaining upon exit (it bounced off of a soft-cover 1" thick text-book after tearing/denting it heavily). Here is what the round looks like:
The round on the left punched the cinderblock. IN/out both sides, hit the book, dented/tore and bounced off.
The round in the middle is a pulled, unfired projectile.
The round on the right first hit a 3-1/4" thick 1/2gallon cardboard milk-carton full of water, immediately after, a 1" thick soft-cover dry text-book, and immediately after that, it penetrated fully through 2 gallons of water in the form of plastic 1-gallon conventional milk-jugs, and then was found in the bottom of the milk-jug behind them. It expanded to 0.32" by 0.49" at the minimum (measured the narrowest distance "between" the "petals") and maximum (measured across the farthest spanning "petals"). The hole in the cover of the book leads me to believe that it was fully expanded by the time it left the 3-1/4" thick milk-carton, as did the resounding SLAP! of it hitting said book (I was shooting suppressed and using electronic ear-pro. The "SLAP!" was insanely loud.) and it obliterating the cardboard milk carton.
All-in-all, it's a sick round and a great addition to my stash. It will run great out of my 10.5" SBR, and should expand effectively out past the 200 yard mark. Should run about 2475fps from that barrel and the effective expansion threshold is around 1800fps.
*Testing conducted from a 14.5" barrel at roughly 15 yards. As a size-reference, the pulled projectile mic's 1.038" in length.