Just finished up testing the Wolf 124gr 7.62x39 HP round from my Krebs AK-103K. The test was shot at 15 ft, 75 degrees, and 300 ft of elevation and the Clear Ballistics FBI spec gel block was used with 4 layers of denim.
-2207fps, 1341 ft/lbs energy
-The round didn't expand per se; but the jacket did tear open (see video below for the specifics)
-Deepest penetration point was 31''
The manufacture of the gel block, Clear Ballistics, claims their gel meets FBI specs for testing. I calibrate my gel per their specs prior to testing and use 4 layers of denim per IWBA protocol.
However, by no means am I saying this test is a substitute for the great work industry professionals like Dr. Roberts and others do. I'm just a shooter that likes to learn about the products I use.
Here's the video of the test:
Wolf 124gr 7.62x39 HP Gel Test HD Video Link